Why does there ALWAYS have to be a romance?!

[Dominique]

I was interested in checking out the The Creeping, until I learned from some reviews that there's an utterly unnecessary romance that takes up half of the story.
Why?! Why add a pointless romance/love triangle to a mystery novel?!
I had the same problem with Bad Girls Don't Die by Katie Alender. I adored the book, but found the relationship between Alex & Carter to add absolutely no purpose, unlike her relationship with Megan.
At least in the Hunger Games, Katniss' & Peeta's relationship did serve a purpose. I also learned that Gale was originally going to be Katniss' cousin, until executive meddling made Suzanne Collins change him into her love interest, which is a real shame.