Refs are human. They are susceptible to crowd and player influence. Unless robots are employed, that will never change. Fans of each team think they are swayed against their own side as they only remember the negative decisions and not the positive.
The mindset of having to moan about every refereeing performance regardless of result will always be alien to me. The result doesn’t seem to matter to some people. As long as they can shout corruption in the designated threads, they’re happy and anyone who doesn’t have the same need is contrarian, condescending [add other adjectives] etc.
The explanation ”just look how we are refereed” isn’t a reason. it’s a gut feeling based on tribalism. Refs will always have to make marginal calls. Some will go for your team and some will go against it. It’s the nature of the game.
Ultimately, people love a good moan.