CRJ700 Captain reported gate return for anti ice warning messages resulted in maintenance failure to correct issue. Captain also reported when aircraft was re-positioned the company intended to put aircraft back in service.

Narrative

Our flight departed normally from the gate in ZZZ this morning. The ramps; taxiways; and runway were contaminated; so we taxied with the cowl anti-ice on; and turned on wing anti-ice and continuous ignition during the before takeoff-below the line checklist. Power application was normal. Shortly after the takeoff roll began; both R Wing A/I and L Wing A/I caution messages illuminated. We rejected the takeoff; completed the Rejected Takeoff QRH; and exited Runway XX at taxiway 1. We contacted maintenance control; and returned to the gate per their instructions. Just prior to parking at the gate; a WING OVHT warning illuminated. I instructed the first officer to turn off the wing anti-ice. He had already turned the wing anti-ice switch off as part of the after landing checklist I called for during taxi-in. Fortunately; we were nearly at the gate; so we finished the taxi-in; and the warning extinguished after being displayed for 5-10 seconds.I called Maintenance Control back; wrote up the discrepancy; and waited for on-call maintenance. Once he arrived; Maintenance Control sent the mechanic the AMM (Aircraft Maintenance manual) paperwork to perform an operations check:Operational Test of the Wing Anti-Ice Control and Indicating System"After reviewing the paperwork; I expressed concern that many of the subtasks would require use of the Maintenance Data Computer (MDC). The MDC was on MEL; and had erroneously reported our wing anti-ice issues as a COWL anti-ice failure (and thus was unreliable). After explaining this to the mechanic and a different maintenance controller; the new controller sent paperwork for a new ops check:"Operational Test of the Wing Anti-Ice Modulating and Shutoff Valves" The detailed description of both tasks makes it clear that both would test the anti-ice valves; but the new test would NOT test the temperature sensors; the cross-bleed valve; nor the control panel. The first officer and I assisted the mechanic with this new procedure; in hopes that it would find the problem in the system. We were not optimistic; as we; as well as the original maintenance controller; suspected that it was likely a sensor issue.The ops check ran successfully- there were no faults detected. The mechanic signed off the discrepancy; and as far as maintenance control was concerned; the aircraft was returnable to service. I indicated that we had not found the source of the failure; no less fixed it. As Maintenance control could/would not investigate further; I determined that the aircraft was not safe for revenue service. I contacted dispatch and the chief pilot's office; and refused the aircraft for revenue service for the following reasons:1. The MDC fault prevented us from determining the true cause of the warning and caution messages.2. The ops check we performed was not the one we should have been running. It was selected after maintenance control realized that the failed MDC prevented us from using the proper. It was; in essence; an inferior procedure that provided insufficient diagnostic information; and permitted no maintenance resolution. It returned the aircraft to service in a strictly legal sense; but left too many unanswered questions. Legal; but not safe and not smart.3. If the wing ovht message returned during takeoff; it would require a high-speed abort.4. If any of the messages returned in flight; I would be unable to continue to ZZZ1; as icing conditions existed and were forecast there. This might require me to divert to an airport that was ideal for aircraft safety; but substandard for passenger comfort and safety.Since we did have an aircraft that was legal to fly; however; the crew and I agreed to reposition the aircraft. The dispatcher was able to provide us with sufficient fuel in a now-empty aircraft to make sure we had numerous places to take the aircraft out of icing conditions if we experienced any further anti-ice system issues.On final into ZZZ1; the R Wing A/I cautionmessage returned. As we had already descended below the icing conditions and were below 1000 feet; we decided the safest option was to land at ZZZ1. Taxi to the gate was normal. I re-entered the discrepancy in the maintenance logbook following shutdown.When I agreed to reposition the aircraft; I was given the impression that I was doing so in order for maintenance to complete the needed repairs. I was disappointed to find out that it was the company's intention to operate the aircraft in revenue service with no further maintenance action planned.In a not-quite related issue; but on the same flight:The ramp agent at ZZZ seemed determined to stand in the doorway to the flight deck the entire time we were waiting for maintenance to arrive. I asked him several times if he was okay; and when he didn't get the hint; asked him not to stand in the doorway to the flight deck. I did this because: -he was in the way of the first officer and I exiting the flight deck; -was obstructing my communication with the flight attendants;-It was just -strange- having him loiter there well within my personal space for no reason;-It is not appropriate for him to monitor my flight deck every second of the maintenance delay in hopes of an update that would not be forthcoming;-I knew that I was going to be making some calls to dispatch and maintenance that could be easily misconstrued by non-flight personnel; painting the airline in a bad light if repeated with poor attention to detail.-Most importantly: it is not his duty station. He has no legitimate business loitering there.I suppose I could have explained more forcefully; but I was attempting to be kind.To prevent a repeat of Ramper-without-borders; when I was speaking to the first officer or the company; I closed and locked the flight deck door. At some point; one of the ZZZ personnel came onto the aircraft for an update. When they saw the closed flight deck door; rather than knocking or speaking to the flight attendants in the back; they decided to call our company and tell them that we had "locked ourselves in the flight deck". I'm sure that the ZZZ personnel were upset at the delay; but this kind of we vs. they drama is just unprofessional. Vigilance is important; but the most extreme vigilance doesn't preclude a knock on the door. Using vigilance as a cover for petty behavior is just plain old petty behavior.I doubt it will happen; but if someone would contact them and encourage them to maintain their behavior inside the norm; I would appreciate it."