What's the rationale for funding those niche sports?

Mostly if a university gets some extra no-strings-attached funding it will set up a new research lab or endow a new chair or build new buildings or perhaps just stick it in the bank or give all the senior administrators a raise.

They could get this windfall money by cutting funding to rowing, but they don't. Is it somehow advantageous to invest sports money back into sports?

I know there's a mandate through Title IX to fund women's sports, and sometimes they have to be pretty creative to find "sports" they can spend enough money on that engage the women students, but that doesn't explain what I'm asking about.