I like Judy's voice acting; I also had a friend like her as a young man that I felt compelled to rescue from the stuff she was dealing with then my (now ex) wife got jealous and forced her out of my life. That aside, Panam did nothing for me. As a player, I wasn't interested in trying to conquer the ice queen who put active effort into keeping distant and saying "no" when I showed interest; she went out of her way to friendzone. Fine, moving on. As V, ok she's not interested, guess it was all about the job and family for her, I'm losing my mind and my body is rejecting me. I've got much more important things to deal with and, even if she did appeal to me, I'm not one for demeaning myself by begging for crumbs of affection.
Maybe for some folks, it's because Judy's a mandatory part of the story from day one; we're led to her and encouraged to feel empathy for her because we've been screwed over by the same people in some ways. Judy is pretty much the only character the player has any meaningful relationship with past Act 1 so the player easily has the most history with Judy when they're finally gaining some confidence in their abilities. Toss in that she's linked to our first lead and it's easy enough to see where folks might think she's their "best chance".
Maybe life as a merc doesn't lend itself to having many friends, but Judy was the only character (besides Johnny) that (in my perception) V is allowed to build any kind of relationship with romantic or otherwise. Judy's apartment isn't too far from V's, so it's easy to stop in for a chat to catch up where River and Kerry are on the edge of town and we only see Panam if we go way out of our way to see her (or fast travel, I suppose, but it's more fun to drive everywhere). Help Claire get revenge for her husband and she won't even acknowledge it the next time you see her at Afterlife - it's fine that she's not a romance interest, but not even a friend? It's like that for pretty much everyone we meet in the game except for Judy. We get to know her well enough that she even gets a glimpse of Johnny.
My first playthrough I also took game concepts at face value - the Relic is killing V and haste is critical. Judy and Panam are mandatory to finishing the game, but Kerry and River are side quests and I didn't even meet them until my second playthrough. My first time through V was female and up for pretty much anything, so it wasn't a big deal to hook up with Judy.
At the end of the day, it's just a game, folks are free to enjoy their single-player experience however they want. If they get extra enjoyment out of spewing on forums it's no skin off my back and I'm free to engage or not.
tl;dr the game more or less forces the player to bond with Judy, she's the only character scripted to take a real interest in V romantic or otherwise.