At first look, Hay Day looks like one of those "Clash of Clans" type of games (city builder, trading with other players, attacking other players). Those games are not accepted to the site anymore because they are not speedrun-able: They are designed with lot of annoying idle elements in mind, so the more progress you have on the game, the longer it takes for you to do any action. There is not really any goals to those games, so any goal you have in mind will be arbitrary by definition. Plus those games can be considered multiplayer, based on how the game manages it.

Also, if the only thing you can speedrun in the game is its tutorial, that should give you a clue that the game is a lost cause from the beginning.

If the site moderators come off as rude, that's probably because they've seen many submissions like this. But I don't think they're treating you unfairly:

@Oreo321 already explained how "Hay Day" is an "endless game with [an] arbitrary [goal]." Dumb Ways to Die is a different style of game, but one that is still an endless game with an arbitrary goal—play the same minigames either for a high score or to unlock characters on the title screen. In any case, there's not too much room to optimize the minigames, and no way to optimize the structure of the game, such as which minigames appear.

Acceptable games for this site are going to be games with more formal structures, as detailed here. This isn't just arbitrary, but because speedruns of these games are themselves less arbitrary and more popular as a result. Exceptions are made for games which have existing, healthy speedrun communities; if you're committed enough to build those with these games, I wish you luck.

The only way it would be accepted to the site is if you managed to build a community of many people speedrunning the game. That's why I wished you luck—that's a very tough task.

A game not being accepted to the site doesn't mean you can't post your own speedruns on YouTube, though.

If you think a game meets all the standards, then you should definitely request it. The worst thing that happens is it gets rejected and you have to post speedruns somewhere else. I would always recommend writing a detailed description in the additional notes section to improve your chances of getting the game added.