The FF Wiki is... notorious for rampent speculation that can't get removed because there's no offical documentation that says a lot of the speculation there is wrong. I... really don't trust any of the speculation that comes from there.
One of the things that gets glossed over with Vincent is that he is a Turk. So... he can't really have a good background himself. Or a good reputation. The guy's skill set is probably something along the lines of assassination, kidnapping, etc. Lucrecia is absolutely right to call Vincent out on saying she's wrong to do what she's doing when he's the one who probably has killed people already. I mean... yeah, Vincent likes Lucrecia. But that's kinda like saying the assassin bodyguard gets a crush on their protectee while the protectee is more interested in a coworker the protectee knew already. And at the time, the coworker had a brilliant career ahead of them and didn't have a reputation of being bonkers crazy.
If Vincent was anyone else, Lucrecia wanting to stay the hell away for him makes... a lot of sense. It would be like wanting to not get too comfortable with oh... Tseng... or Rude. Trusting any of the Turks with just about anything has "bad idea" written all over it. Because everyone knows the Turks' sense of morality is... all but non-existent (which is one of the ironies of the Turks' character as a group). At most, the only thing the Turks really care about is each other. Thinking a Turk has a better sense of morality than you, a "normal" member of society (IE: not going around being a paid assassin) does? Yeah, right.
So yeah, I can understand Lucrecia wanting to get married to Hojo and do science with him. We don't see any sign Hojo is unusually crazy before they marry. And I underscore "unusually" for a reason. Sicence at Shin-Ra in general seems a lot more... lax on a lot of things we would have issues with today. And Lucrecia worked for Shin-Ra already. So she (and everyone else at Shin-Ra) probably has a more flexible idea for what "human" experiments looked like. At least... before things went really wrong...