They don't like him much.
Secretary of Defense Pete Hegseth had a similar approval rating. Roughly 45% of respondents said they approved of him, while 50% said they disapproved.
The kid of a friend is in the military, and while I don't think this person's opinion (hates Pete) is anything but anecdote, I do get the sense that hating Pete is a perfectly normal thing to do. It isn't an opinion people feel they have to hide.