Within any group of views, you will find extremists. They are not interested in nuanced discussion of facts, and have developed such a distorted view of the world that factual statements get confused for opinion (and the reverse...confusing opinion for fact). This is true for RW and LW, MRA and SJW, etc, etc, etc.
The primary problem is whether the behavior you observe is one of the extremists, or if it is the standard for that group. Personally, I haven't run into SJWs that are that over-the-top, but I don't doubt you've encountered some. From what I've read, that kind of opinion is on the fringe of the overall SJW movement.
This is different from a number of other movements where such behavior is the norm. For example, members of white supremacist groups behave in a similar way as a rule, not as an exception.