You can talk about the advantages of federation and the both ideological and technological considerations involved without telling people things that are patently untrue.
#ActivityPub is _not_ easy to implement and we severely mislead people by telling them that it is.
There are _not_ good, general libraries for it
Implementing AP does _not_ mean that you can now federate with anyone using it
I'm not sure whether people's insistence of these is naïveté, wishful thinking, or outright lying.