The bro's take
Free tube sites pay their bills with ads, and some of those ads are pop-unders, fake download buttons and malware. uBlock Origin blocks them before they load, uses little memory and is completely free and open source, with no 'acceptable ads' deal.
It works best in Firefox, where it has its full feature set. On Chrome the original version is being phased out, so use uBlock Origin Lite there or switch browsers.