What I Dont Understand About Twitter Followers

Here is the thing I don't get about twitter. People follow people they are interested in and want to know what they are doing (unless I am missing something). What I don't get is why people follow me, but then bitch about what I say... repeatedly.... and often times will say "Who gives a shit" in response to my tweets. Well I guess you do jackass or you would not follow me. Here is a good example... Last Friday I went with my wife and daughter (it was my daughters birthday) and she REALLY wanted me to get my toenails painted. So I put up a twitpic of it: and this jackass incredibill who has been following me for years but is always the first one to bitch comes out with: Now don't get me wrong. I am all for free speech and if this failure at life wants to spout his bigoted comments at me then go ahead. He is one of many that like to make personal insults I receive every day. I am a big boy and have put myself (and my toes) in the public spotlight. What I don't understand is why people devote there resources to following people they do not like. Maybe someone can explain it to me?