I hate Touma's harem antics, too, and the yuri being played for laughs is annoying, but I'll play devil's advocate here and mention that it doesn't seem to be limited to yuri. Straight couples also fall victim to this.
Whenever a character has a crush on another, their whole personality is thrown out the window and replaced with a shallow, cartoony cardboard cutout that obsessively and one-sidedly obsesses over the object of their affections. I don't think I haven ever seen a character (that didn't start in an established relationship) whose crush is taken seriously at all as of yet.
The only "pair" that doesn't fall victim to this is Last Order/Accelerator, and that's mostly because they're less of a romantic pair and more of a big brother/little sister pair, so they're never subjected to romcom antics.
For example, Misaka is a cool but slightly childish ace with a strong sense of justice, but when Touma's around, she devolves into helpless tsundere #127456. Kuroko is a diligent and straight-laced ally of justice. She's also smart and talented in her approach to crime-solving. But whenever Misaka Mikoto is around, bam, she devolves into an incredibly dumb psycho lesbian. Index is a kindhearted, incredibly friendly girl whose smile can melt hearts, effectively working as the heart of any group of friends she's on, but around Touma she's helpless tsundere #5243426. Mugino is a freaking cold-hearted villain who starts growing a heart after going through some messed up crap. She's selfish and uncaring most of the time, but around Shiage, she mellows down to the point that she's nothing more than some maiden in love.
tl;dr: The Raildex author is incredibly bad at writing romantic interactions/feelings overall, not just the yuri kind. He really should just keep romance out of his works and focus on friendship and camaraderie, IMO.