IME, of those supporting gay marriage, a very small number support or glamorize Che Guevara. I would guess only a minority knows who he was.

I suspect many with the poster/shirt just think it looks cool.

Try Moneydance, which is close to QuickBooks for a small business, depending on your needs:
http://moneydance.com/

In my limited experience it's well-designed, well-supported, and geek-friendly (extensible with Python, open API, etc.). It appears to be multi-user but I've never tried that feature.

I assume it still runs on the Win8 desktop UI? Or are Win8 users unable to use Firefox outside a VM?

As you demonstrate, ignorant, hateful people can be found everywhere. One way to spot them is that they depict the world as one group vs. another (Jews vs. Muslims), and talk about a group of people as if they are a single-minded whole (Jews do this, Muslims do that) rather than as millions or billions of individuals.

My reading of history is that the hateful people are the ones that cause the most trouble, independently of what other group they belong to.

So yes, email him to give him an idea of how much actual interest there is so he knows the readership will be there.