On the other hand, I believe that all those arguments could have been used against him:

The boss information was correct until his weapon was drawn
-All a ploy to gain our trust

Kirito yelled out that the attack wasn't as written
-You didn't yell it out fast enough to save Diabel. It's just your farce to make it look like you warned him. Nothing was changed. You Beta Testers knew everything from the start.

Third, he risked a lot himself and took much damage that fight, so it's not like he didn't contribute and risk much. Save for Diabel, he was the most important factor in them leaving that fight alive.

-You knew the boss's attack patterns. There's no way you would have died. You joined this fight to get the final-attack bonus item. Diabel died. We're just lucky to be alive. Who knows how many of us you'll sacrifice for your plans in the next fight.

The book kicked back off of the paranoid guy's arguments, but if Kirito tried arguing here it would have backfired.

All the mob knows is that their leader died (who they didn't know was a beta tester, and Kirito doesn't want to reveal that neither) while following an apparently sound plan, and they've got someone surprisingly strong that they can pin the responsibility on.

He'll have enemies from the group he was in, and he'll have many more enemies he hasn't even had a chance to meet yet.
Why would they try to fight him and risk being killed?