Wondering if anyone has advice, or if this is just normal?

My 2 year old was always kind of "High needs baby." He always needed 100% attention as a baby. He loved being praised as a toddler. He isn't really around other kids all that much, other than his brother. Who he is wonderful with 80% of the time. But he does this thing and I have no idea how to correct it. Or if I even can? I have honestly never seen another 2 year old do this.

So, say we go to the park. And there is anothwr kid who just walks by him....Or even just walk past him.....He will scream??? Like high pitch scream? Just a short burst. I try and explain. "We have to take turns." Or "It's okay." Or "Say hello! They want to play with you!"

But he mostly just yells at them!?!?!??!?! Why??????? Ah! I never really made it an effort to put him into group play dates and I feel like I'm paying for it. He has no idea how to take turns or socialize? No one just screams in our house?? Like ever. We always "Use our words." Does anyone else's kid do this?? Any advice?