I think the general public (as opposed to her rabid fans and equally rabid haters) had positive feelings toward Meghan because they felt that (i) Harry loved her, (ii) she had actually worked for a living, and (iii) people were genuinely excited to see a racial minority join the royal family. I think they were willing to overlook the social climbing and Diana worship rumors due to those two things.
So I think she really shot herself in the foot when she decided to start her royal career with a slew of events that highlighted her ambitious social climbing and Diana obsession (royal appearances and tours, couture fashion, family drama, and celebrity friends). It’s almost like she was going out of her way to prove the haters right.