Just because his personal belief is traditional marriage doesn't mean he's some huge anti-LGBTQ monster, all he's simply said is the choice should be up to the individual states to rule on, which includes more than just ruling on same-sex marriage.
He opposed a recently passed bill in North Carolina that prohibits people from using public bathrooms that dont align to their born gender, hes openly stated transgenders should use the bathroom they feel comfortable in
He supported amending the 1964 civil rights act to include a ban of discrimination based on sexual orientation.
He has tons of gay friends who speak highly of him, even gay people he knows a bit but aren't necessarily friends, including Elton John (Trump happily celebrated his marriage), if you ask any gay person who's been in contact and spoken to Trump a few times they'd all be surprised his personal belief is traditional marriage.
He was the first private Palm Beach club owner to openly admit a gay couple, and stand up for the rights of Jewish people and African-Americans to be able to join private clubs as well.
Not to mention all the times he's donated to AIDS research and charity organizations focusing on AIDS with gay couples.