Most biologists accept evolution because they do things which require evolution to have been true for their experiments to work, and then their experiments worked.
Just like how you hear in the news once in a while "experiment yet again proves Einstein's relativity correct ".
The specific reasons are usually unfortunately technical beyond laymens' understanding.
edited to add:
And I think that is the major reason why there's a disconnect between evolutionary biologists and evolution skeptics.
e.g. I have one tattoo that I partially regret. It's a molecular biology tattoo, not a double helix of DNA or a famous equation that people recognise, but a simple cartoon of a map of a synthetic piece of DNA used for genetically engineering E. coli that is very widely used in the biology community. I did not consider the population at-large at all when getting this. And now I'm asked by people in the street once every two weeks or so, "what is that?". I CAN explain it, but it would take 15 minutes. And even then, in this case, you cannot really understand what the thing is, unless you can understand what the thing is used for. So you're looking at a 1/2 hour lecture for me to be able to explain this thing to some random dude on the street. But when they ask, they are expecting and wanting a 20-second answer, tops. So I give them an answer that's 1% of the truth..."It's DNA". They have a confused look on their face, and I can tell they don't know what I'm talking about, but I don't want to, or feel like I should, elaborate. Every biologist recognises my tattoo immediately, as easily as they would a heart symbol or an inverted pentagram.
In other words, it's not so much that biology is arrogant and condescends to communicate with the rest of the world, but biologists have simply learned that people on the street who question them are not looking for the full explanation that is modern evolutionary theory, (or bacterial cloning plasmid vectors) because that is a week long lecture at least.
Almost every critic of evolution I've read on the internet forums has used words that prooved to me that they don't understand the theory.