Also, I do remember that Meghan did get positive media reception to begin with, especially when she was compared to Catherine. She was called a breath of fresh air unlike boring dowdy kate. I only remember the negative articles started coming out right around or after the wedding. And even then, most people were very positive towards her including myself.
There were racially loaded headlines with racist dog whistles from basically the first moment they started dating, and the press were awful to her. Remember the abuse was so bad, Harry had to release a public statement about it, that specifically mentioned racism? The idea that Meghan had a positive reception at first is revisionist history.
Here on MN the hate and racism was off the charts right from day one. During their engagement there were perhaps half a dozen Meghan bash threads being started per day. Every single thing about her was trashed, there were non-stop lies and conspiracy theories being invented and spread about Meghan, her career, her history, and her family. Racist conspiracy theories about her mum. One specific conspiracy theory so vile I won't repeat it, which originated on a Neo Nazi forum. We've had at least half a dozen posters pop up claiming to have a friend in Hollywood/Buckingham Palace who worked with Meghan and had told the poster terrible things about Meghan, one poster even claimed their "friend who works in Buckingham Palace" had witnessed her hit Charlotte. Many many threads deleted for racism. Non-stop dog whistles, and even one swiftly deleted posted who used the N word in full. Hell so many Mumsnetters got banned for how extreme and racist their Meghan hate was that they went off and created their own rival forum where they talked about the best way to create new accounts to get around the ban, discussed plans to mass-attack pro-Meghan posters to try to get them banned (eg by abusing the report feature, or following pro-Meghan posters around making nasty comments on anything they said outside of royal threads), even tried to dox pro-Meghan posters.
Just absolute unhinged non-stop hatred.
Kate had a really hard time and she continues to have an unfairly hard time but nothing like the obsessive hatred Meghan received, and the racism aspect plays a big part too. Kate got called a gold digger and workshy, she didn't have Neo Nazi terrorists calling for her children to be killed, or 50 threads a week from people who spent 24/7 fixating on how much they hated her.