Actually, when you make money from your post, you are technically using the logo to earn income. Fair use would be if you were explaining something about Steemit and showed their logo as part of their business, then fine.

Ignorance is not an excuse. If you want to wait for a lawsuit... carry on, but be warned. I'm no lawyer either, but if it was my logo and you made unauthorized derivative works from it, I would be suing you. I did need to look all this stuff up since I do own my own logo's and what you are doing is not the way I understand the law.

I'm just trying to be helpful here, but if you wish to ignore my advice, it is no skin off my nose. Do as you please.