For an academic in a Divinity school, an uncaring but professional environment is a dead canary. It means something much worse than the lack of sympathy in that moment.
But, if that doesn't make sense to you, how about being systematically passed over for a promotion because of your political views?
It's hard not to see this as being a crappy place to work if you put yourself in his shoes.
I don't know if anything in the letter is true or accurate, of course, but that anecdote seemed to be illustrating a subtle point for people with better insight into his school than most of us have, and was definitely not the only reason cited (or else it really is just a weird thing to mention, which is possible, but, regardless, it's far from the only complaint)
But, if that doesn't make sense to you, how about being systematically passed over for a promotion because of your political views?
It's hard not to see this as being a crappy place to work if you put yourself in his shoes.