Now that I stopped laughing, I can give you a reasonable answer.
Yes, they are. But, then, handing someone a couple million dollars in the hope that it will turn into 50 or 100 million is an irrational act, too. So, it's hard to get too upset over them being purely irrational.
There are two problems:
1) VCs/Investors are sheep.
This is the infuriating one as it makes most of the VCs/investors you deal with effectively useless. To the point that when pitching to them the goal is to trigger that behavior (the term is FOMO-"Fear of Missing Out" aka: acting like sheep). So, if everybody is investing in something, everybody will invest in something. Until it blows apart. If you just want funding, try to pitch something which runs downwind of this tendency.
2) It's really all after the fact rationalization of "I don't like/trust you."
This doesn't make me mad--I just would rather a VC/investor just say this. But they won't turn you down definitively for lots of social reasons (mostly hoping they don't turn down the next AirBnB/Uber/etc. and get laughed at at the country club). I would actually respect someone more who simply said "My astrologer says the signs aren't right. KTHXBYE." Or, even, flat out "I don't like you." I'm cool with that--my personality is straightforward--most people like it, a few call it tactless and arrogant. If you're one of those I rub the wrong way, fine, we need to find different dance partners.
The problem is that too many investors want you to jump through hoops when they're looking for reasons to turn you down. Generally, you should simply read this as "No" and move on. It's like trying to date a pretty girl--when she gives you some excuse multiple times, she's probably telling you "No" but trying to keep you in her list of options just in case.
Upshot: raising money is hard work. If you want to sit in the big chair, you had better be prepared for the slog.