Most feedback is useful to some extent, including complaining on reddit about the things you don’t like or want changed.
It lets Riot know something about what players want and how they feel.

Acting directly on any one source of feedback, however, is a terrible idea.

As a community-facing dev you should read reddit.
And then for every highly upvoted suggestion, or common complaint, you should consider:
How it compares to other sources of feedback. (Whose existence a lot of vocal redditors seem to have a hard time grasping.)
If it’s a seemingly good idea: what the cons are, and vice versa.
In fact, all the unexpected ways you can think of that it may impact other things.
How it matches your current design goals and vision for the game.
If it makes business sense.
Etc.

As a redditor it makes sense to make your voice heard.
But it also makes sense to not expect Riot to act on anything you want. Even if a couple thousand other redditors agree with you.
And Riot ultimately not doing what you wanted doesnt mean they ignored you.

In a world where feedback towards devs was less hostile it would make sense to explain their decisions a lot more, but that’s not the world we live in.

Riot do a lot of dumb things. “Not listening” to reddit isn’t one of them.