I think what you are doing is a little over the top. What will you do when bub starts to crawl??
My DS sucks on shoes etc. I didnt want him sucking on toys at mothers group either but when he started to crawl that ment I had to stop him from playing with things he really wanted to play with, how mean of me!!
Other peoples fingers in your bubs mouth, however, I think is rude. My FIL did this and he sucked his fingers before hand, Im guessing to "clean" them then felt around DS mouth for teeth, that made me furious. I didnt say anything though.
Public tables, thats a bit over the top but if you are worried you can buy anti bacterial wipes. My sis buys them and wipes shopping trollies with them before her DS gets in them. It will make you feel better about bub touching things anyway.
My DS has only been sick twice and he is now 9 1/2 months and he doesnt have anything sterilised.
It seems that if you get sick, baby gets sick and if baby gets sick you get sick.