How do I politely but sternly, ask for my baby back when someone is holding him and he's crying?

My sister-in-law, grandmother, and mother-in-law take my son from me when they first see him and won't give him back when I ask. Repeatedly.

My 5 month old starts crying because he doesn't see them very often and they tend to be loud, so he gets scared. He wants his mom clearly. But when I say "let me see him for a second" they tell me "no no. He's fine." As his cries get louder and tears are forming. My sister in law went as far as telling me to "go away you're ruining it". And I'm left standing there watching my baby get more and more upset. I went to take my baby tonight and my mother in law WOULD NOT LET GO. I was so defeated and feel like a weak mother for letting her win and my baby lose. Ofcourse she eventually handed him back when he was crying so hard and arching away from her that she couldn't hang on well. I realize I need to stand my ground but everyone is so goddamn sensitive if you say anything people get mad and hold grudges. And I'm treated like the family asshole. I'm told im over protective by these people constantly. I don't want my son to feel like he can't other trust people. How do I ask for my baby back and have them understand that it's what's best for him at that moment, and hand him tf over?