There are thousands of literary magazines worldwide, and at least ten for every type of writing in existence. Some publish so many genres that they refuse to classify them. Others only focus on one type. And then, there are the magazines that are primarily fiction or nonfiction, accepting only a few poems per issue.
"Okay... so? What's the problem with only taking a few poems?"
Including just a few poems often isn't done because the editors love poetry or because they want to give readers a variety of content. Nope. It's a tactic used by editors (of mostly print literary journals) to fill as much empty space as possible. If there are three empty pages that no story will fit, a few poems can easily add content in whatever constraints.
"More opportunity is good for poets!"
True, I suppose. I guess the idea of utilizing poetry the way florists use baby's breath just feels wrong to me. Yeah, it makes what's on offer look more plentiful, but it's still more of an enhancer than its own attraction. No one is going to press the baby's breath from their bouquet as a keepsake. No one is going to take the few poems on offer as a selling point or something to care about.
And people should care about poetry, especially the editors considering it for a place in their magazine. It shouldn't be an afterthought or a garnish. If editors are going to offer it, poetry should have a rightful place in the pages... dedicated space where it can stretch and blossom. To have it as anything else says poetry is fluff, that it's lesser than other types of writing.
"Won't sneaking in poems expose more people to poetry?"
Yes, if readers don't skip over them. If the editors take the same care with them that they do with their short stories. If everything is favorable, a few people might find their way to poetry. The biggest positive of poems being treated like a vase someone buys to accent a bookshelf would be if poetry gained new fans. Sometimes, that's all you can hope for. Sometimes, it's all that you need.