I can’t understand why you find it suspicious, no one is forcing you to install them, they are just suggestions, most of which are are already popular downloads of 4/5 start ranking by users.
I have never been concerned with keeping it fast and clean, all I was/am interested in is keeping it where it supports my browsing habits. I have many add-ons installed currently 33, some of which arr security related (NoScript, ShowIP, WorldIP, CookieMonster and RequestPolicy), but most help me with tools used in browsing and forums, etc.