If Core's goal is to get a large percentage of nodes to drop their filters then of course they are going to attack the credibility of other implementations that go against that. I'm not a huge fan of Luke for a lot of reasons, but Knots has a good track record so far and this controversy is drawing more eyes to his code which is also good. It's almost entirely based on Core anyway so there isn't much that needs to be reviewed if you already trust Core anyway.

It depends on what you mean by fork. It has multiple meanings in this context. Knots is fully compatible with Core. The Core apologists know that Core's actions are indefensible so they must attack Knots with FUD. The MIT license thing might be part of the problem.