Endorsing a candidate or a party places an additional seal of approval on the actions and beliefs of that candidate/party. There’s a difference between saying “between ham or fish, I pick fish” and “I believe fish is the right choice for everyone, fish has qualities that I myself would like to emulate and believe in”.

She’s a pop singer who seemingly upset a lot of internet people (but not many real people) for saying “yeah, I’m voting for Kamala, but I won’t endorse her because the democratic party hasn’t done enough for the LGBTQ or minority groups and I’m not keen on the Israel support thing”