I've never owned any of the above mentioned boats, but I've sailed on several. They're just fine for their intended use and the're not "garbage" just because they're not ocean passage-making vessels.
While I don't necessarily agree with the wording he used, I think the spirit of his statement is true. Those brands simply don't build their boats as well as other manufacturers have in the past.
Take a look at any of the higher quality built boats (Cape Dory, Bristol, etc) from the 70s and you'll find bronze components that will last longer than us, well supported rigs, thick and well laid fiberglass, and overall quality construction throughout. Compare that to say, a Hunter, whose components and construction are clearly cheaper, of lower quality, and not as well thought out. While some of the obvious construction flaws are inconsequential on their own, it does represent the amount of time the builder used to built the boat correctly and the mindset throughout the build process. I know this is a corner case, but I remember hearing a story where a new Hunter 30 was purchased and the owner found a crack developing along the bow after a few months, they later found that the fiberglass cracked when it came out of the mold and the builder put some sort of paste in the crack. That does not inspire brand confidence, even if they addressed it properly.
That doesn't mean they are "sh**", though. They have a purpose and they fit it well, but I wouldn't expect a Hunter or Catalina to last as long as a better made boat, especially if it's left neglected for any period of time. I've seen several of the higher quality boats left neglected for years without major structural problems, but the same can't be said of the cheaper brands. That said, I'd sure rather live aboard a Catalina 27 than a boat that is aimed at being more seaworthy, all that space is really nice.
Also worth pointing out at least one Catalina 27 has circumnavigated, but required significant work, much more than a boat that was well constructed from the start.