I would pick one recent episode, the CVE-2018-17144, the latest found Bitcoin vulnerability that could have crashed the network. It was reported by awemany, one developer of Bitcoin Unlimited (Bitcoin Cash).
As far as I know, awemany while testing BCH found one error and decided to test it with BTC which he found that it had the same error. Well, he took the initiative to test BTC, he lost his time and he reported the issue.
What happen after that, the disrespect, the opinions that came up concerning the quality and competence of Bitcoin Cash developers, it contains much of this "Bitcoin maximalism" spirit underneath.
I have no idea what you're talking about when you mention "what happened after that".
Who precisely was disrespectful, where, when?
Cooperation should be appreciated, any altcoin developer who contributes and do a good job should treated professionally and with respect. People should be motivated to contribute more.
Absolutely. To the best of my knowledge, most developers get along quite well when it comes to mainly "technical" issues.
Quarrels about "politics" aside,
qualified developers, at least, do.
There have always been clueless non-techies who bitched about people like Mike, later on about Gavin, etc.
Also, on a more personal level, quite a few developers have had their fair share of bitching.
Nothing about that really matters.
People are people.
I stand by my claim that there is, in fact, no such thing as "Bitcoin Maximalism" (at least among intelligent, educated people).