Not if they were trying to assassinate a dictator or something

It can depend in my eyes

No, considering that there are individuals who are so dangerous they have to be killed or they will kill everyone around them.. many superheroes commit murder, any willing killing of another living creature is murder.

It is about intent - sometimes keeping someone alive is infinitely more of a crime than killing them (such as Batman continually keeping Joker alive - especially when even he admits doing so kills hundreds of people daily).

Also if someone attacks another with intent to kill or seriously harm them and get killed by the would-be-victim the victim still commits murder - but the alternative is just letting the criminal kill them or worse.

No. Murder is even considered standard villainy in most works.

It depends on the context.

It depends on the heinous standard of the work. For example, a murderer in something like a modern Disney movie would definitely count, because Disney is known for its light-hearted material. This wouldn't be the case for a horror movie however, and definitely not for exploitation media. For those, the MEH would be crossed if the killer employs somewhat creative torture that makes their victims suffer, or rapes their victims to show how formidable they are.

Look, being a murderer is pretty despicable, but the point is that you can go worse.

Murder is standard villainy, so no.

Murder is standard villainy, it can only count if it goes way beyond standard villainy (e.g. Walder Frey leading the Red Wedding)

The Joker, at least to Superman anyway

Ah okay, @RandomUser69420 , so strapping a bomb to a tow truck is a moral event horizon? But killing someone is a standard villainy?