About the specific edit you seem to ask about:
While a moderator also edited your question, the edit that removed tags came from me (I’m not a mod).
Why I removed the microdata tag: Microdata is just a syntax, while Schema.org can be used with various syntaxes (commonly JSON-LD. Microdata, and RDFa). Your question doesn’t seem to be about how to use Microdata (i.e., the attributes
itemprop etc. in HTML5), but about how to use the vocabulary Schema.org (i.e., which types to use, like
VideoGame etc.). Or in other words: Neither does answering this question require that someone knows Microdata, nor is it likely that someone could learn something about Microdata when visiting this question.
Why I removed the rich-snippets tag: Your question doesn’t seem to be about a Rich Snippet or how to get one. Just like in the case with Microdata, someone doesn’t need to know anything about Rich Snippets to answer your question nor are answers likely to be about this topic (as you didn’t ask about it). However, if you do want to know something about Rich Snippets in this context¹, I think you should ideally state this in the question, and in that case adding the rich-snippets tag is of course appropriate.
¹ note that Google’s Software Apps Rich Snippet does not seem to be available to every site, currently