Think a lot of people feel that that, OP, for reasons well rehearsed.
It's a major decision with ramifications going forward for future generations - many of whom did not have a say as they are too young to vote, whilst some of the older generation are gleefully talking about getting back "their" Britain - when the reality is they won't have to live with all of the fall-out.
In this sense it is quite different from a general election as there really is no second chance, no balancing different policies, and compromises. It really is a stark black and white, yes or no.
Both campaigns were badly run, short on truth and low on facts and rational discussion. The claims about immigration and that the money "saved" will go to the NHS have been acknowledged as "mistakes" already.
The terribly reality of the situation we are now in has been confirmed by the markets crashing, political instability and many prominent Brexiteers being very quiet - because they have no idea what happens next . Despite the political simplistic rhetoric , we can't just up and leave the EU without very serious consequences.
Unfortunately there has been a lot of bitterness in this campaign, probably because the stakes are so high...and the fact that it is such a momentous decision that cannot be reversed at the next election or mitigated in its effect through parliamentary process as all other legislation is just makes this more so.
Are you being unreasonable? Personally I don't think so, as I would feel the same. Over time, chances are you'll feel differently, rediscover common ground. But you can't help the way you feel right now. As long as you're not being overtly rude, just keeping your distance, can't see that you're being unreasonable.
If you still feel like this in the coming weeks, perhaps you can politely remind them of their views when they start complaining about interest rates/having to get visas/whatever other fall-out comes back and bites them personally.