I don't understand...

[Foo01]

Wrong casual is a playstyle....

Casual is playstyle is wrong? Says who?

... militant is an attitude. ...

Says the militant elitists attitudes. It is the elitist trying to force people to play their way their style that is the problem.

....Things need balance. ....

Sure but the balance you are talking about is completely bogus.

Never giving polite advice when things are going badly is the opposite side of the guy that rages and swears at everyone when they make a mistake....

Both the term "polite advice" and "going badly" are vague and subjective. So much for the false equivalence.

No one said never giving advice, no one is telling you to stfu and play. Wiping 15 times might be frustrating to a speed runner (where wiping once means rage quit for the elitist), but it is perfectly ok to casual players trying to figure it out. Not clearing content and running out of time on the first try is also perfectly fine. Uncalled for advice is not going to be well received, so called "polite" may not be so "polite" on the receiving end.

On the other hand being the elitist that rages at everyone else, that is absolutely uncalled for and absolutely not OK. It isn't about being militant (excluding trolls of course), it is about having a friendly environment for everyone to play the way they are comfortable with.