A relic/mythic/emperian shouldnt have to solo or need.
Someone with good gear and atmas can solo a mob too, just that emps are so easy to get that chances are someone with the things I mentioned has one of those too.

Honestly if you want to skillup or make your own effort to killing and take offence and people one shotting stuff just ask nicely in party chat, very few people will be an ass about it. Well geared players do like showing off but if you talk nicely people usually act in kind.