(without the ghastly mobile)
These are bots. You cannot stop them from following you unless you alter your settings to restrict followers by making your tweets Private. Obviously, that would be counter to your goals.
You have two choices.
1. Ignore them.
2. Block them. On the followers page, each profile has a little cog icon. Click on that, select Report, click through to report them for spam and block them. Gradually they will go away until the next lot lamps on you.
These bots scan the twitter firehose to look for key words. Tweet the word soviet and a soviet bot will respond. Tweet depression or suicide and a love bot will tell you you are loved. Tweet kickstarter and you'll get kickstarter bots and so on and so on and so forth.
You'll learn the bots by their non-sequiturs and RTs of obvious spam. A few months ago, I got dozens of gamer bots following me, all telling me the Beatles couldn't hear their amps because of the screaming.
If you are a steady tweeter, you will build a following and these bots will be a mild nuisance and a smaller percentage of your followers.