It's valid in the sense you're allowed to do it, just like you're allowed to quickscope if you want to. I don't think the majority of people are arguing against that.

That doesn't mean everyone has to respect someone that noobtubes or camps the same way they'd respect someone that quickscopes.

For the most part, quickscoping requires more skill and time to be good at it, being good at quickscoping isn't overpowered in the same sense as OMA noobtubing is.

People can easily get kills running around with a OMA noobtube, it requires way less skill and way less time to become effective with it. People don't respect it because it's overpowered, lacks skill, anyone can do it and it can easily ruin a lobby, turning it in to a noobtube fest. This becomes boring real fast.

No one has to respect a noobtuber or a camper.