URF is polarizing. Honestly, it is my least favorite or the RGMs, but that's largely because I don't play any of the champions that best abuse the game mode, and I also recognize outright that I can't play quite as fast as the mode requires. But just because I don't like it doesn't mean I feel like the mode should never come around. Nobody is forcing me to play it when it's out!
Beyond just that, though, the topic of URF on the boards is frankly a bit overdone. Especially threads asking for it to be a permanent mode. In explaining why they only bring URF around every once in a while, Riot effectively answers why they wouldn't make it a permanent mode, too. It's just not going to happen, and the topic itself has been beaten to death, hence the downvotes when it comes up again.
What's more, Riot has to get all the RGMs up and running for the new client still, and they've stated as much. Back when it launched, they explained that they'll be introducing the different modes to the new client over time. So while I have no doubt that URF will be coming down the pipeline on the new client, we just have to be patient while it gets there. I'd guess they'll probably be working toward bringing it out for April again, if possible. But again, demanding URF back into the RGM when it's not even ready in the new client yet is just pointless, hence the downvotes when it comes up.