I think that if one were to draw the line between tolerant and intolerant ideologies, that line shouldn't be drawn based on the content of the ideology but rather how that ideology spreads. Specifically, based on this quote
> they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols
The only ideology, the only Belief, that should not be tolerated is the belief that ideology must spread through violent means.
That in and of itself is a belief, but it is a belief that can be discussed through rational argument, and only calls upon violence when all else fails.