It is strange that this became a thing that everybody is willing to make a stand on. 

I think it comes down to each side feeling there is a threat to an essential aspect of bitcoin: the BIP 110 side sees spam as a threat to node runners, the Core side sees overly strong spam mitigation efforts as a threat to Bitcoin's incentive structure (hmm, that isn't quite right when I say it: what I mean is Bitcoin's" game theory" but that phrase gets used so widely as to be almost without meaning).

Agreed. But then again, the opposing side also turned  their stance surprisingly quickly into a hill-to-die-on mode.

Vocal parties on either side acted like monumental dickheads (still are? Haven't been following the soap opera in a while.) 
And I don't care who was the first dickhead.

unboiled

I think this wouldn't have happened if the changes in core were not pushed so agressively.