I’ve had people be mean but never like that. It’s none of their business what she gives or does not give in the collection plate. It’s between her and God.
We have attended the same church for many years. Started out small, now 25 years later, I guess you could call it a mega church. They’ve never taken an offering...there are boxes at the rear of the church to put your offering in. Doesn’t seem to have diminished the giving. Saves time too, passing the plate in a large church, no matter how many ushers, can take a bit of time.
As to meet and greet, after the worship/song service, they say have a greeting, and then have your seat. I know people who will not shake hands, due to fragile health etc. It is an awkward time for them, as it is for people who don’t know others.
When I was in college, I attended a church where they welcomed guests by having all the members/regular attenders stand, and the visitors stay seated. Maybe that was more effective than having a visitor stand (as churches I grew up in did)...but still you’re singling out folks.