How hard would it be to get groups as an untwinked Ranger?
 

By untwinked, I mean literally with no starting gear/funds at all, just rusty weapons and cloth armor out of the gate, and maybe Fine Steel/Ringmail by 20+.

Where can I go on Green where any Hybrid class with the exp penalty won't get treated like absolute scum of the earth?

As a Ranger? Probably will not be very in demand past a certain level. Once you can’t keep up tanking wise with Pallys and SKs you lose a bit of steam in terms of which melee hybrid a group will want. Before that point even Bards and Monks can be effective tanks depending on the content so you’d have competition there as well.

And of course if a Warrior has good gear I’d take them any day over a hybrid (and even without gear since someone could just root the mob if the warrior loses aggro)

If you are a Wood Elf Ranger, other Elves will group with you, in Faydwer. Everyone else will probably turn their nose up to a dirty R*nger.

Like I said before, where can any Hybrids be welcomed into a group without people shitting all over them for their exp penalty?

Just stay in Faydwer with your kind, as long as you segregate the world will be better. The zone bonus in Kedge Keep will make up for you being born with an exp disability.

I just find it hard to believe that Hybrids are hated that badly among class purists.

I (among many others) leveled a ranger from launch 1-50, with no twinking and pretty much tanked (while also pulling) the entire time.

A couple tips:
1) Use a nice 2h from lvl 20-40
2) Form your own groups
3) Be nice to people
4) Use your abilities, but don't over use them (i.e. don't just auto-attack, but don't flamelick and root everything for no reason either—in other words don't be bad)

1-40 was really easy tbh. 40+ people start getting more stingy about grouping with hybrids, but if you have a good reputation and a bunch of priest friends, it won't be too bad. Tanks are in high demand after all. Just make sure come 40+ you invest in some AC and HP gear.

I've been grouping constantly as an SK since green launched. You'll never have to worry about people complaining about hybrid penalty. No groups give a shit. As far as tanking ability? You probably won't be the first choice as a ranger but in a lot of groups cases, beggars can't be choosers. Tanks are always in incredibly high demand and if there's two healers in a group they'll probably take a chance on a ranger. Otherwise you'll always happily be added in as a dps if there's a dps slot open.

As main tank I love having a ranger in the group so long as they're willing to pull, because it gives me time to med between fights.

I had no trouble getting groups as an untwinked ranger on green. You can tank in a pinch and groups like rangers as pullers, especially in outdoor zones.

If you're worried about gear, you can get some nice weapons for cheap now. Ebony Bladed Swords are like 50-100p and really solid ratio plus a proc at 25. Gigantic zweihanders are like 400p maybe. Farm up bone chips near the freeport zoneline in north ro, and sell them to fund a suit of banded armor and some decent starter weapons. You'll be fine :)

Solid ratio based on what? To me, a solid ratio is 0.50 or better. For a Ranger, I'd make an exception for Lamentations because even though it's just shy of 0.50, it has a nice Str/Sta/HP boost on the side.