The times I have visited CNET pages in the past was to find specific information. If such information happens to be in deleted articles, that would reduce my interactions with CNET in the future.
I think they should archive the old articles or even offload them to Wayback willingly, but it's possible some of the articles they're purging aren't worthwhile. If I write up an article about a cat playing on a scratching post, there's a good chance there's nothing unique or valuable about it and it doesn't need to sit around gathering bit rot :p