Flight Instructor with student reported a NMAC during approach with an aerobatic aircraft that was maneuvering over the airport.

Narrative

While conducting an Instrument Rating Airplane training flight with student using a view limiting device our aircraft was conducting the VOR-A approach. When about 1 mile short of the missed approach point I observed an aerobatic airplane in a near vertical high-speed climb while over the ZZZ airport. Weather was clear and visibility unlimited.FAA has issued a NOTAM advising that there may be aerobatic aircraft within an area as defined as 1NM radius of ZZZ airport; surface to 4000 feet Daily. I was aware of the NOTAM. Apparently an aerobatic club has convinced the FAA that this is a safe operation and allowed such activity. The airspace is not restricted from normal use by all other aircraft; thus we used it at the same time as aerobats. Aerobatic activity and routine training around this airport do not mix safely. Why in the world would FAA allow low altitude aerobatic activity at the same time/place as intensive other training. In particular a published instrument approach such as VOR-A at ZZZ. All kinds of training activities penetrate the 1NM radius of the NOTAM area. ZZZ Approach control does their best to warn pilots of this activity. The aerobats do not own the airspace and it is not restricted from normal use. Just the NOTAM advising of aerobats.As this event took place I was reprimanded by the pilot's ground observer on the CTAF for being in 'their' airspace. The speech by the acrobat pilot had a strong accent. A woman radioed on the CTAF as well with a similar strong accent. Reprimanding me for being in 'their' airspace. I informed them that they do not own the airspace and that others might be there at the same time. Many training airplanes come to ZZZ to practice Instrument Rating procedures. This is not the place for a FAA sanctioned 'aerobatic box.'Apparently FAA has issued a waiver and 'Waived' FAR 91.303 '(c) to allow acrobatic flight within the lateral boundaries of the surface areas of Class B; Class C; Class D; or Class E airspace designated for an airport.'This is the 3rd like occurrence for me in particular. The first time I informed the FSDO and others in writing. No action has been taken for several years. As a FAA certified pilot for XX years and retired FAA Safety Inspector (OPS) for XY years I think it's important to bring this to the attention of anybody who could move the aerobats away from an airport. It's UNSAFE and should be discontinued immediately. Do we need a mid-air collision before something is done about it? I think not. It's like the Blackhawk on the Potomac. FAA need to take a stand for safety.