>>98994593Eh the show was highly inconsistent about how anti-social Dexter was, some episodes did have him as a friendless loser who barely comprehended anything that didn't have to do with science(indeed a common running gag and/or plot catalyst was Dexter misinterpreting some social or language construct and treating it literally and applying science to it with extreme results), while others treated him as a fairly normal(if nerdy) kid who just happened to have a funny accent and the knowledge to make the laws of physics his bitch
Similarly the show was inconsistent about how dumb Dee Dee was(some episodes she was basically special needs, while others had her as relatively average in book smarts, but very wise in more emotional and social matters), or how old she was meant to come off(some episodes she'd act like a first grader, others like a teenager)
TLDR: both Dexter and Dee Dee were written extremely inconsistently even by cartoon writing standards
Mandark on the other hand was pretty consistent, the only real variable was how evil they'd depict him in a given episode(ranging from just wanting to one up Dexter in matters of science to wanting to rule the world as a vicious tyrant)