you can't care about what others in the gym think...i use to do the same thing, but it is a bad mentality and will only lead to doing more weight then you should causing improper form.
i am new to hst, but not new to lifting, but i am sure the begining of the 15s would make anyone feel silly. i suggest concentrating on your form and make sure you obtain hypertrophy, afterall thats what were all about! in time if hst works like i hope it will then you will be the one laughing in your head at the begining of a new cycle when you are bigger then the guys who looked down upon you.
also, most of the time, no one cares but you...trust me, it is probably mainly in your head, if anything your lighter weight makes them feel better about themselves, but i doubt they are laughing at you on the inside.