As a DM, I don't want to have to deal with people in my game who are going to be defensively rules-lawyering me all the time and are assuming at every turn that I'm there to screw their PCs over. D&D is a game for DMs too and that's just not my idea of a fun time.Because a lot of people don't entirely trust any GM from their history, but they'd still like to play. As the saying goes, "Its the only game in town".
There's piles of players out there looking for a table, and a lot less DMs. If a new player (obviously this is more a problem with new groups because long-established groups hopefully trust their GM...) rocks up at my table and their playstyle is this hostile and oppositional, I'm going to quickly decide they're a bad fit for the sort of game I'm running and find someone else.