This is not a legal advise. It’s an explanation of a license. That license is quite clear for people who know what it means. The problem is, that (especially in Europe) this whole licensing and privacy thing is over the top in regards of what is legal and what not. I have customers who have a simple private blog fretting about the terms and conditions of how they are allowed to say the name of their medication on their blog. Honestly… it’s going over board with this whole “legalese” thing.
MIT License allows you to have a website with that theme. Commercial or Private. No need to say “I am using XY theme”. If you want to sell your site you have to disclose that you are using that theme. That’s all.