I attend an ASD Peer Support group at University. I've tried to participate in the group over the last while, although, unfortunately I have pulled off lately due to the the poor response from some members.

I'm upset with 2 people.

Overall, I would say that most of the members that participate in the group are fine, however, there are one or two who only come to the group to rant or talk incessantly about their interests.

Common symptom of aspergers.

I have tried to take a rational approach and give these members in particular, more time to talk - this doesn't work.

Who are you to "give" them anything?

I have tried to interupt and/OR instead give signals that I'm bored with their incessant talking - and of course, this doesn't work either.

Another symptom of aspergers. If signals don't work on you why would they work on the people of this support group? By interrupting them you're displaying the same behavior they are but they sound like they're handling it better than you are.

(Some of these people are as old as 25, so they should've developed some social skills by now.) So it is clear to me that these members don't respect my personal boundaries nor care for my input, for whatever reason I don't know why.

Blatant assumption and another symptom of aspergers which you seem to have forgotten.

I decided not to attend thereafter, because these two members were up to their usual antics and I can't deal with rude behaviour.

Their behavior is not rude, you're jealous.

I tried to interject numerous times, only to be interupted. Only twice was I able to get a word in and even then, they didn't reciprocate. So it wasn't great at all, but part of me wonders if it was my fault and I wasn't pushing enough in making conversation? It's hard to asses a situation without external input, so I don't know.

Again you try interrupting them and get upset when they handle it maturely. Mock concern entertaining the idea of controlling the topic.

The behaviour of the members was irritating obviously, but I do wonder if their behaviour was caused by anxiety or maybe even enabling?

Projection.

I just wonder, at what stage do we as humans tolerate behaviour like this? And how do we decipher between rudeness caused by Aspergers/Social Ineptness and/OR someone being rude and arrogant?

The people you are upset with are also humans. Body language, reading about aspergers syndrome may help you empathize.

I just find it hard to believe that a High Functioning 25 year old could be so Socially Inept as to think that it is normal and acceptable to talk over people constantly.

Ending your message with another judgement. Have you read the definition of arrogance?

arrogant
[ar-uh-guh nt] 
adjective
1.
making claims or pretensions to superior importance or rights; overbearingly assuming; insolently proud:
an arrogant public official.
2.
characterized by or proceeding from arrogance, or a sense of superiority, self-importance, or entitlement:
arrogant claims.

Sound familiar?