EXACTLY! I know it's a theory that used to be popular a while ago but I think it just has no real textual justification? Even her offhand comment about marrying all of her suitors was more about *their* disappointment than anything (since she seems to be perfectly content and in love with Arthur).
It also bears comparing this with the other major Dracula victim we met so far, Jonathan. During his ordeal in the castle we noted several times that it was his dutiful obedience to Victorian standards of education and politeness and societal expectations that helped considerably trap him.
If he wasn't so married to the Victorian idea that foreign peasants cannot possibly have anything interesting to say, he maybe would have heeded the warnings more. If he wasn't so eager to be the best and most polite host ever he might have demanded to go back to the village as soon as possible. Of course, ultimately he probably would have still been trapped, but the added horror of Dracula forcing the pretense of politeness upon him wouldn't have happened. And it's worth noting that it's only after the last veneer of that politeness is lost that Jonathan starts truly fighting.
Time and time again we see that Dracula feeds on what's available but when he can choose he picks the most virtuous, nicest, kindest people around and makes a point of toying with them, dragging their death as long as he can and psychologically torturing them until they are a shade of themselves. It would be easy for Dracula in England to pick prostitutes and transient workers, or maybe even patients from the mental asylum literally next door, and as long as he kept switching it up people would barely notice! But instead he goes for a girl who is surrounded by people who adore her. Lucy might come to his notice out of sheer bad luck (because she's a sleepwalker and therefore more vulnerable to his mind control powers is my guess) but he picks her over and over despite the ever-increasing risk because he LIKES her and he likes her BECAUSE she is so innocent and precious and loved by many.
I feel like if there's a critique of Victorian social mores in Dracula it goes in the opposite direction and it might be unintentional on Stoker's part. I think Stoker just picked a type of victim that would make the story all the more tragic, since they would be easy to fall in love with, which makes sense for a horror author, and people instead tried to turn it into some sort of morality play. Stoker has been very heavy handed about his social critique so far (see: Mina and the New Woman) so I think if he wanted to make that point about Lucy, she would be completely different as a character.
Also, not to turn it into an even longer essay, but "deliberately picking the nicest most virtuous people and destroying them" was the modus operandi of the titular Vampyre from the short story by John Polidori that came out in 1819 (so before Dracula). Like I'm not a Stoker expert but I think it's safe to say that in terms of tropes there would be precedent for this idea of the vampire targeting innocence.
