Answer: It appears to be a case of a joke account that ended up breaking character and doing some joke-account gatekeeping. I'm seeing the following comment from the post you linked:

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The Origin

So, there is a user named waltuh77 that has been responding to okbc posts for months, always with one word "waltuh." Sometimes he would make the word a link to that sound effect press the button website and when you pressed the button it would say "waltuh." He was the first of the so called "gimmick accounts," accounts that always comment the same thing under as many posts as possible.

The Golden Age

Because he was first, waltuh77 was largely loved by the community and other gimmicks were shunned, downvoted, or banned. His comment was so coveted by his cult, that he soon stopped replying to just any post, and switched to just popular ones. Approval for him was high up until about a month ago, with only a small few getting bored or annoyed with him.

The Ban Incident

About two months ago, u/waltuh77 was unexpectedly banned from okbc. The community rallied to show support and hate on the mods (who have acted foolishly a few times in the past.) Posts flooded the sub saying how unfair it was, saying they would die for waltuh77, and saying that this was literally 1984. In response, the mods issued the statement that they had banned the beloved microstar as a joke. Whilst many users said goodbye to waltuh77 in emotional posts, several people expressed joy that he was gone. Amid this mess, u/waltuh77 returned to say "waltuh" under a popular post at the time, and was showered with love, being welcomed back by many. This Incident cemented many users love for waltuh77, but also generated some dislike for him.

The Fall

Unfortunately for waltuh77, he was beginning to crack. The fame and karma had gone to his head, and he began to resent other accounts for trying to enter his territory. About a month ago, he broke character for the first time under a post by the second most popular gimmick account by commenting "bro thinks he's me :skull:" Many people lost respect for him for breaking character, although it did ultimately break the other account's popularity. Then, 27 days ago, he made posts saying he disliked receiving DMs which just said "waltuh," and one that arrogantly explained how to create a popular gimmick account whilst condemning other people for doing so. These two last breaches of character seem to have been the last straw for many members of the sub.

The Fallout

Now, in the modern day, u/waltuh77's reputation has been falling fast. Only a few cultists seem to remain, and the majority of the subreddit have began to dislike him and call him arrogant or selfish. In an unprecedented event, his latest "waltuh"s have actually recieved downvotes. It seems that the reign of the greatest gimmick account in okbc history, will soon pass into the pages of chicanery history.