“you wouldnt need a tshuva for that. its a straight up issur “
It may appear that way, but situations in life are not always so simple. If it is clear that there is tumat ohel for an aino yehudi, then what was the question? Why would one great Rav ask another great Rav such a simple question? And why would such a simple teshuva be codified (by Rav Moshe himself) in a book of teshuvot if it’s that obvious?
Life is not that simple. It’s easy to pasken from behind a keyboard. I asked a Rav and got an answer.
See Yorah Deah 372:2, where he says that it is proper for a cohen to avoid walking over kevarim of goim. From his lashon (and also the Tur’s) it’s clearly not forbidden. Maybe not preferable.