Someone offered a reasonable explanation and counter to your original post and you responded by implying they didn’t even write it themselves. That’s a poor reaction. Instead of making an accusation without offering evidence, you should actually respond to his points.
Dipper’s a twelve year old dealing with his first crush and his first rejection. I don’t know if you remember being that age or having those experiences, but for most people they’re an emotionally trying time. And in Dipper’s case it’s further complicated by Wendy probably being one of his first and only friends.
He’s got a bunch of photos because he has a passion for photography. You focus on one that’s taken from behind but every other one is taken from the front or side and Wendy is clearly aware he’s taking them. She’s even smiling at him in most. It’s no different from the pictures Mabel has in her scrapbook. Which probably has its share of unknown pictures, frankly.
Dipper’s not a stalker, he doesn’t try to keep chasing Wendy after she turns him down. He respects her decision and doesn’t try to change it. But as he says himself: just because he knows she isn’t interested doesn’t mean he can just turn those feelings off.
Mabel also had a page in her scrapbook about her failed romances. At one point, she was struggling with those memories so much that she considered using a memory gun on herself to remove them. So she has no right to criticise when Dipper has known Wendy longer and was far more emotionally involved with her than his sister was with any of her crushes.
As for why he kept them as secret, maybe he knew his sister and friend would react like that: criticising him for his struggle instead of helping him through it. Which is just sad, honestly.
I have many, many issues with this episode, but the biggest one is Mabel’s behaviour. I love her and have staunchly defended her against her haters. But in this episode, I saw how she treated Dipper after everything she and they have been through and felt genuinely angry.
Dipper is a good kid who’s struggling with new feelings he doesn’t fully understand and doesn’t know how to deal with. Of course he’s going to make mistakes, that’s his whole thing. He messes up and tries to learn to be better. And sometimes he doesn’t always learn, or it takes him longer than it should. That’s what makes him human, and relatable, and good.
But here, instead of helping him, the writers decided to mock and insult him through the characters who should have supported him. And all over a crush they chose to continue instead of giving it closure. They’re blaming Dipper for a problem they made and don’t know how to solve.
This is Gravity Falls at its worst.