B737 MAX 8 Flight Attendant reported hearing a high-pitched; whistle sound coming from the L1 door during all legs of the route. Flight Attendant reported the sound to the flight crew; who did not notify Maintenance according to procedure.

Narrative

I am writing this report in regard to an incident that occurred on Day 0. Our assigned routing for the day was ZZZ-ZZZ1-ZZZ-ZZZ2-ZZZ on Aircraft X. During the first leg from ZZZ to ZZZ1; all four flight attendants reported to the Captain a high-pitched; dog-whistle-type sound coming from the L1 door. Upon landing in ZZZ1; we discussed the issue with the captain and agreed to observe if the sound would go away after opening and closing the door for the next flight.On the return leg from ZZZ1 to ZZZ; the noise persisted and was slightly worse. We again informed the captain; and maintenance met the aircraft. Maintenance cleaned and greased the door seals. On the next leg from ZZZ to ZZZ2; the sound returned; even higher in pitch. The flight attendant crew notified the Captain and First Officer that the sound had not improved; and we expressed that we were uncomfortable continuing without further evaluation. We informed them that the next appropriate step would likely be a pressurization test to ensure the issue was fully resolved.Upon arrival in ZZZ2; we were surprised to learn that the pilots had not called maintenance; had not contacted the company; and had not entered the issue in the aircraft logbook; despite multiple reports from the flight attendants that the problem continued. The same noise persisted on the final ZZZ2-ZZZ leg at the end of the night.After arrival back in ZZZ; the Captain called me into the flight deck and asked; 'What's this door issue about?' I responded; 'The same issue that we had on legs one; two; and three.' He replied; 'So if it is fixed; why should I write it up?' I said; 'It hasn't been fixed; the issue is still happening.' He then stated; 'But maintenance came and cleaned the seals and said the door was fine.' I replied; 'But the sound is still coming; and so no; it is not fixed.' The captain then pointed out that the first officer was a flight attendant for another airline for nine years and said that he 'thinks the sound is fine.' I explained that I bid specifically to work on the Boeing aircraft and that the sound is not normal and is concerning not only to me but to the entire crew.The captain then said; 'Ever since I met you; the first thing you said was if anything goes wrong you're going to call fatigue;' referencing a previous comment that had been made as a lighthearted joke. He continued by saying that I have a terrible attitude and that I need to fix my attitude. During this exchange; the captain appeared visibly angry; his face turned red; and his tone was raised. The interaction was unprofessional and created an uncomfortable work environment.The flight attendant crew experienced significant ear pain and difficulty equalizing pressure throughout all four legs of the day. The continued presence of the high-pitched sound from the L1 door suggests a possible pressurization or seal issue that was not fully corrected. Despite our repeated reports and discomfort; the issue was not logged or re-evaluated as required.This situation appears to be a direct violation of 14 CFR §121.703; which requires carriers to report mechanical irregularities; as well as 14 CFR §121.701; which states that before each flight; the pilot in command must ensure that mechanical irregularities disclosed by the flight crew are entered in the aircraft log. FAA AC 120-72A and FAA Order 8900.1 Volume 3 also specify that all discrepancies reported by cabin crew must be documented and resolved or properly deferred per the MEL. The flight attendants complied fully with 14 CFR §121.563 by reporting the issue multiple times to the captain.Overall; this incident raises serious concerns about compliance with FAA mechanical reporting procedures; proper communication between the flight deck and cabin crew; and professional conduct. The flight attendants did everything required of us under the FARs; yet our concerns were not taken seriously; and the aircraft continued to operate with a potential door or pressurization issue. I would like to know that the company will take action regarding this event.