the reason Albus seems so less affected is because he thinks about Gellert a lot. about when they were together and how, if Gellert could stop being such a stubborn genocidal cuckoo, they could be together again, but it's never gonna happen. he thinks about Gellert almost all the time, but he knows there's no hope left.
Gellert, on the other hand. ooh boy. Gellert doesn't think about Albus. no sir. of course Queenie knows this isn't true AT ALL. Gellert likes to think he's over Albus, like, completely. he doesn't need him. he doesn't love him anymore. and he certainly DO NOT think about holding Albus and kissing him under the moonlight again. no no (again, Queenie is onto his bullshit).
so that's why Gellert was so affected by their physical contact after so many years. the yearning, the pining, the hope that someday his love would join him again and they would conquer the world together. he wasn’t prepared to see Albus so up close (yes, i remember the first scene of the movie. it's different). he wasn’t prepared to fight against him. and he absolutely was not prepared to be touched in such a gentle and adoring (even despite the context) way.
that “who’s gonna love you now, Albus?” wasn’t an abusive boyfriend yelling shit and trying to be demeaning. thanks to the titan of acting, mads mikkelsen, we could see, clear as daylight, it was out of desperation. he was trembling and on the verge of tears.
he yelled: “who’s gonna love you now, Albus?”. but what i heard was “please. please don’t leave me again. I love you. I need you. please don’t leave me”.
Just rewatched the Secrets of Dumbledore and it's like Albus Dumbledore going 24/7 "Oh btw I was in love with Grindelwald... Did you know? 'Cause I was in love with him. The summer I fell in love with Grindelwald... You're wondering what this bracelet thingy is wanting to strangle me? Yeah that all happened because I was in love once. With Grindelwald. In case you didn't know. Oh, did you not know? Indeed, Grindelwald and I had the hottest summer of love. You know, when I was in love with him..."
Bless him. They're still so clearly in love with each other.