I think it's because it's "classics." Your first couple of years excepted, everyone hears about a text years before they read it. By the time they read it, they already know a lot about it, and they read it closely and systematically to get a deep understanding of it.

There isn't a firehose of new text being created in Latin, and you never (or very rarely) scan over something to find out what it's about, extract a quick fact from it, or decide if it's worth reading. You know what's in it, you know the standard take-away from it, there's a good chance you've read the highlights in translation already, you may even know one or two hair-splitting academic controversies about it, and you are sitting down for a good hour or several hours with it. It's a completely different kind of reading from scanning a web site or a newspaper to find something worth reading more closely, looking for the answer to a concrete question, or scanning something to decide if you can afford to not really read it.