It’s so bizarre to read this in the present, knowing how incredible TNG was, but I get it - the original crew WAS Star Trek to them.
The dedicated fans revived this series in syndication, well after it had gone off the air in 1969, and felt attached to the characters that they had obsessed over between then and the 1980s. Like modern fans, they thought that departure from what they knew would ruin it.
I wish I could go back in time and tell them that TNG is going to rock.
I recall this being posted ad nauseum on r/startrek, and the comments were always full of people using it to dismiss any and all criticism of Discovery and/or Picard. Nice to see that not being rehashed here.