My question is somewhat similar to this question, however I feel I have a different situation in which my question is not covered by the answers stated.
I have a player in my campaign group of 5 players who is constantly "jumping the gun" on a lot of my custom built scenarios. I've seen this as very typical of a rule lawyer, however I do not believe he is doing this out of malice/etc., just simply not understanding the situation fully. I should note, I try to always adhere to the RAW, and I make sure all players are aware that if you can prove it is RAW then it will be used. Here is a better example from a recent campaign we played...
- Players entered a crypt to fight the main boss. Players (through trial & error) discovered his AC was 18.
- RuleLaywer argued that it was too high given their level, and impossible to get that high if I had used the monster manuel/etc.
- I told him it was done using the rules, exactly as written with no hand-waving, he simply did not know the full details yet.
- RuleLawyer then proceeded to be toxic for the rest of the fight making jabs every time someone missed an attack (to my annoyance, even on rolls of 1-2).
- Party killed the boss, and looted his body, he was wearing some magical armor that improved his AC, that the party then took. (The armor was from the DMG, and I even had lore around how he obtained the armor (that the players discovered shortly afterward).)
- Player then stopped complaining, since he now understood the full details.
He is a long-standing member of the group, so it's not that he's new. He is also not new to RPGs. His problem seems to generally be more along the lines of, "I think this is not fair — even though I don't know the entire situation". Kind of like a rule lawyer who only read ¾ of the book before quoting rules.
I know indirectly that his actions have bothered more than just me. I've had at least one other player come to me saying they were annoyed by his attitude, saying something along the lines of "I wish he would just play the game and stop making a big deal about this and being so snarky". Although I have to take that with a grain of salt since I don't think that player likes him very much (out of campaign).
How would you generally deal with someone like this? I don't want to have to give out story/etc. aspects of the campaign in advance just so he does not complain, since it would ruin the exploration of the campaign.