About YouTube, complain to YouTube. Complain to Google about Google Translate Element. For other translation services, complain to the developer of that translation service. You don't understand anything about what this addon does.

There is no way to automatically insert to a specific sites. Because in many cases, it is assumed that you want to translate all pages written in a foreign language.
If the "Insert Google Translate Element automatically" checkbox is checked, It will be automatically inserted on all pages written in a language other than the language specified in "Languages that do not automatically insert Google Translate Element". For example, if you are a native speaker of both English and Japanese, you can write "en,ja" and it will automatically be inserted into all pages written in a language that is neither Japanese nor English.

It's useless to say anything to someone who doesn't read the release notes. Your choice is right for you because uninstalling is the safest option.

But noboy can prove that the software is bug-free. There are probably bugs that you don't notice.

Thank you. I don't speak Russian. The translation into Russian was done by volunteers. Was there something that was difficult to understand? You can improve the translation. https://crowdin.com/project/googletranslateelement

I have released a new version including your translation.