This is a very tricky situation, not so simple like spammers, over-bot abusers or friendly upvotes.
On one hand, @Greenman writes big posts about himself, his life and crypto experience, which sometimes is very interesting​ to read. He also upvotes quite a lot of users, who write comments on his posts. Usually, these are minnows with no money who are trying to get a big upvote.
The bad part in this situation is that it looks like he does not read comments at all or at least this is just my impression and there are lot of spammy comments like "hey nice post" , "well done follow me ", etc.
As results we see a shit tone of comments (some good and the rest shitty ones).
Now, on the other hand, he is replying to those comments and upvotes himself, which looks bad, but makes some sort of sense. He is compensating his upvotes to comments of others so it would look fair.
Now the question is , would it be the same situation when you write in someone other's post a comment and upvote yourself? Is self-upvoting allowed or not? Where is a line?
Personally, I think it looks a bit as overuse of your power. You can reply in your own post comments couple of times and selfupvote, but replying to every shitty comment and writing the same, well not so good. On the other hand nothing prohibits to do that. Self-upvoting your comments in others posts would be almost the same and would look ok to most people in Steemit.
My verdict - the amount of comments self-upvotes in your own post should be smaller. Quality of the comments should be higher. Then it will look better.