Earlier quoted context omitted.
Sam is loyal and devoted to Frodo, but there is zero romance between them. I don’t see how one could read that in the book. Sam even marries Rosy and has umpteen children. Is Gollum gay for Frodo because he caressed his knees while on the path of Cirith Ungol?
I can't help but agree having read the books umpteenth times... even in retrospect I find it more likely that Tolkien added Rosy into the narrative simply to make it clear that Sam was a heterosexual and that Frodo was merely an asexual eccentric like Bilbo. I don't think there is any problem or harm in reading them as bi or gay, but I'd love to read a better case for Tolkien having written them with that intention.…
Heterosexual succession (or, rather, the succession driven by the family unit) was (and still is!) a driver of “ordered society” and given both Bilbo and Frodo subverted this because of Tookish events (Bilbo driven by, and Frodo basically suffering the fall out from) Sam marrying Rosie is effectively the natural end point of things. He is able to marry her because of what came before, and their marrying is a signal that those times are over.
I’m going to have to re-read Tolkien now. I haven’t since I was 15, and this thread made me realise I ought to pay it another visit!