Your source makes the supports the claims you make, but it itself does not source (some of it more grievous) claims.

I'm willing to accept that the claims of them suing various people. But I wouldn't call these cases frivolous per se: They could very well believe that they were denied participation in a parade on a discriminatory basis. I wouldn't necessarily say I think it is the right approach to take but the examples they give are not that absurd in today's world. (And could also be the work of but a small subsection of the group).