Well, to discuss your latter point (and not just because I'm one of those posters you're talking about!), I bring up the Stargazer as an example. I *think* within the show the Constellation is regarded as a non-too-elegant design, and even Picard confesses that the class and the Stargazer itself are not sleek, efficient, even favorable designs anyway. But Picard told Scotty that sometimes, if he could, he'd trade the E-D for the Stargazer because of that sentimental value. There's no accounting for taste, but it can be separate from personal preference of ship. Indeed, Scotty clearly much preferred the TOS bridge rather than its arguably more streamlined, uniformed, and more advanced movie incarnations. The Stargazer and the TOS Enterprise were the ships where Picard and Scotty cut their teeth with, much in the same way that a viewer connects with a particular ship if they watch for a long period of time.
Saying the design isn't 'sleek' isn't necessarily a value judgement - it's just a description. It's just as easy to value 'non-sleekness' as it is to value 'sleekness'. Saying it's inefficient is an in-universe judgement of its effectiveness at doing what it was designed for - something a man who captained it for decades would have to be honest about. Neither is really very connected to the question of what type of design someone prefers aesthetically. (I really have no idea what is mean by a 'favorable' design)
Ultimately, though, my point wasn't about people having personal preferences for one ship over another. Certainly, that's true, but I was talking about the fact that people have personal preferences for certain styles of design over others. That's all these posts about 'character' and 'soul' are - one person just doesn't like a particular type of design and so, even on first glance before the show has had any chance to build up the ship as a character, feels like that design has no 'soul' or 'character'. If the show is particularly effective at making people feel for the crew and making the crew feel for the ship, then many people eventually get over it. If not, you're left with two groups divided solely over the fact that they just like different styles.