Jtdcftul

I have been invited to visit a professor in a different country. I am very reluctant to go. The government of this country is currently under investigation by the UN for suspicions of crimes against humanity targeted at people of the same ethnic background as me. More generally, people from my ethnic background are legally considered second-class citizens (when they are citizens at all) in this country, and routinely get physically aggressed in the street without the police or army doing anything, even partaking sometimes...

How should I explain to this professor that I do not want to go? Should I get into details, invent a different reason?

If I were you I'd have the same concerns. In fact, I'm not like you, and I have the same concerns.

But don't confuse the people of Israel with its government. Certainly there are bad actors there, but I also know many Israelis who are more than decent people and oppose the government actions and attitudes that you worry about.

That said, you may be wise to avoid such a trip. But don't assume, necessarily, that the professor would disagree with your true reasons. There is no way to predict, of course, since opinion about Israeli-Palestinian issues come in "all shades of grey" in Israel.

If it is a question of meeting, rather than visiting the professor's institute, you might suggest meeting elsewhere, say at an international meeting.

To flip it a bit, there are quite a lot of people in the world unwilling to visit the US because of recent trends and attitudes here - and some that are not so recent. And I won't visit Mexico, for example, though I love the place, not because the government is bad, but because of the danger of drug gangs and killings and an ineffective government.

I work in a country where a few colleagues do not wish to visit, for various reasons. Some of these reasons are based on accurate perceptions and others are based on false perceptions. Some of those colleagues have been willing to frankly discuss their concerns with me, and in some cases I have been able to appropriately assuage their fears; in the end, these people came and were glad they did. But some had legitimate concerns or were simply unwilling to budge -- including some close friends and collaborators. I respect their concerns and opinions, and we have continued to work together even though I know they will never visit. I do not think any less of them for this, and I believe they do not think less of me for working in this country.

My recommendation is to just be honest, but don't let your concerns evolve into a debate over political issues in your colleague's host country.

This answer assumes that the professor is reasonable. If you know them, use your social skills to judge whether they are reasonable.

Tell the professor that you don't want to go there for the reason you told us. They will understand (since they are reasonable). If possible, make another suggestion how you can achieve the goal you had.