- There is so much antiviruses,
- Every computer with Windows should have one => every Windows user should have something to tell about software he uses,
- Example question about program making screenshots got 13 answers, even when I know more people using antivirus than people using something different than Print Screen + Paint to make screenshots.
Because not all of us are windows users (like me) and most people who use anti virus software just use what their neighbor had without ever thinking if it is the best tool for the job (100% of all people I know that use antivirus software fit this criteria).
Also Antivirus Software is a pile of snake oil luring you into a fake security thats just not there.
Or it could be that all the antivirus experts hang out somewhere else.
There are many antivirus programs with many (mostly similar) features, and in the areas where they differ, rating these features becomes very much a matter of opinion. The only simple distinguishing feature with some objectivity is price.
Another important distinguishing feature 'how good are they at catching malware' is not something you 'just answer'. The tests are complex, and framed by test conditions so that objective comparisons need study. The casual reader (writer) here can at most point to reviews.
People usually have just one AV program and as long as 'it works' they don't bother tinkering with it. AV is considered necessary but dull. Why would you prefer one over the other as long as it 'just works'?.
Some AV programs have distinguished themselves by things that do not work, like bringing the system to a crawl, false-flagging Windows files, annoying popups, etc - not exactly 'features' that are asked for in the questions.