Just give me a yes or no so I can know whether to get back on New Vegas or not.

Based on some of the videos on Youtube, yes you can help them.

Is that so? Well I will have to look that up.

Based on watching the end slides for HH on YT, it seems it's possible, but I won't say what would make you want to help them since it'd spoil it.

If it's possible, I'd love to know how. I never got a single option in my entire playthrough.

But they're kind of jerks, so I'm ok with not helping them.

You can help them, but it's not in a direct way. I will not say anything more because this forum does not allow it. What I will say is check all of the quests in the HH section of the Fallout Wikia and you will see one in particular that will give you your answer.

White Legs are always hostile no matter what you do.

You can help them to the same extent that you can help the Enclave in FO3.

Completely indirectly and in a lack-of-motive way that makes your character seem like a sociopath.

"Seem like"
Your character's response to two mormons doing mission work in one of the few beautiful places left on the earth is to kill everything that moves.
Seem like.

I will not disagree that it is in an indirect way, but I do not think the only way of helping them requires that you have no motive. I had my character do it because of their connection to the Legion. I made an assumption that there was probably a way to facilitate their victory, and it turned out that I was right. That certainly does not mean that I lacked a motive for doing it.

There are lots of RP motivations you could have for aiding the white legs, or killing them all and let god sort it out:

Working for the legion
Anti-tribal prejudice
Not liking the burned man. would any sane person work for him after he slaughtered the NCR and willingly worked for the legion? you'd be perfectly reasonable to think he had some horrific hidden agenda given his reputation for abject brutality and wanton slaughter.
anti-religious sentiment
greed
vengeance for the NCR

Short answer yes. Longer answer, you won't talk to them either way.

The burned man sir is a wise man and has much heart.

That's one interpretation, sure, but if your character is an NCR loyalist or an anti-legion independent then you'd be reasonable not to trust him.

There's really no benefit in helping the White-Legs. You're really just screwing yourself out a great experience and a bunch of quests by doing so. Even if you're pro-Legion there's no reason to do it.

Sometimes the reason people do things in a sandboxed game is "because I can." It's really kind of why a lot of us play them.

Is there any *good* reason to kill every NPC in the game (save for one, invincible individual) and go marching off to the end? Not really. Have people done it? Sure have.

Personally, I think helping a bunch of raiders is a bad idea.

However, I'd love to be able to enslave them and force them into the Legion.

Why, oh why can't we have a Mesmotron in New Vegas!?