It’s not so much that he’s INTO blowing things up, more so that his spell work is often atrocious enough that things just explode.
I actually have a headcanon to explain this. We can sort of weakly infer that magic is influenced by the caster as well as just the incantation. Lily did a lot of stuff with flowers (even before she could control it properly), Hermione’s magic is always particularly detailed, Ginny seems to have a penchant for nasty hexes, Lockhart is inexplicably good at memory charms. Maybe something about Seamus’ magic just naturally gravitates towards exploding?
Never have I identified with Seamus as much as I do now
https://www.reddit.com/r/harrypotter/comments/gvkjz2/can_we_just_acknowledge_that_the_main_irish/fsqlrh8/
https://www.theguardian.com/books/2016/mar/09/jk-rowling-under-fire-for-appropriating-navajo-tradition-history-of-magic-in-north-america-pottermore
That all seems very weak.