There's a lot of rhetoric flying around, but underneath all that, this is what Knots is about:

Core used to have a mempool policy which set a default limit on certain field sizes... Since most people ran the default settings, it worked and allowed the mempool to (mostly) keep people from abusing the blockchain by using it to store data unrelated to monetary transactions.

But Core chose to remove that policy filter. This fundamentally changed Bitcoin from being a monetary network to being a file storage network..

Knots is a response to that change. Knots restored the field size limits as part of consensus code so it can't be removed..

Knots has no intention of filtering legitimate transactions of any kind, it just caps field sizes to prevent it from being used as anything other than pure money.