My mom when I was growing up found any expression of same sex relationships to be outright pornographic.
I find it is best to be deeply deeply skeptical of anybody defending book censorship because frankly the most common pro-censorship movements in the present US use words like "sexualization" to mean things like "gay couples and trans people exist".
Normal people wouldn't agree with that definition, but they'll nod along with "kids shouldn't have access to sexual material", so that's the code-word that pro-censorship camps used.
This is literally always the excuse used when censoring content from people.
At the end of the day, we need to acknowledge A LOT of the bans were because of racism, homophobia, and other prejudices, and that these "safety" arguments are just made to conceal that.