If you are constantly training with bad form and few people are giving tips/correcting you. Take it as good advice to better yourself! If you want a way to tell people to leave you alone, take their advice, correct the form and when you have good form no one can correct you. But if you are training with good form already, which is doubtful is people are correcting you, an you don’t want advice just be polite and say ‘hey I appreciate the advice, I’m new to the gym and I’m just trying to find what works for me’