Frodo and Sam; Pippin and Merry are classic bromance characters. They borrow upon English male relationships, which are quite effectively captured in the movie Tolkien.
When the LOTR trilogy came out, the question "Do you think they are gay?" was naturally posed. It's a ridiculous question that even at the time backed actors into a corner. What were they supposed to say? When George Takei said "No" to the same question about Sulu, pointing to Roddenberry's original vision, he was more or less shouted down. The ability to talk about art as a set of forms constructed for the sake of the story gets more and more of a beating these days.
The insistence on a label robs the relationships of depth. In Tolkien, the real life character Geoffrey Bache Smith, with whom real life Tolkien was good friends and who died in World War I, is given a possible crush on Tolkien, which crush remains unstated and unreciprocated. The same movie gives Tolkien a batman named Sam (likely invented). The other friends are combative and supportive and daring. Labeling them wouldn't make them more real or vibrant or individualistic. It wouldn't make their relationships with Tolkien and each other any more layered. People can be more than one thing and more than one thing with each other at the same time.
Sam and Frodo are entirely reliant on each other in their tiny band of brothers (unlike in the movie, they never separate in the book). Merry and Pippin are so close that Merry feels bereft when he is left alone with the Rohirrim--the movie perfectly captures this moment in Return of the King when Merry dashes to the outlook tower to watch Pippin ride away with Gandalf.
It seems to me that paying attention to the label rather than to the emotions keeps readers and viewers from noticing the actual reality of the relationships--which would be a pity with such great well-rounded characters.