I can't believe this has two pages of replies.
Here's the deal: People are actually still playing other editions of the game. WotC produces these tiles, which actually can be used with any edition, because they're basically just visual aids, and the game has always used a 1" scale for tabletop maps. The tiles can actually be used for any other game that is compatible with a square 1" grid map, but WotC doesn't want you to buy those other games, so they emphasize only its compatibility with D&D. Since they no longer produce or support previous editions of D&D (with the exception of PDFs of older editions, which probably account for <1% of D&D sales, and so aren't a threat to the new edition), it's safe enough for sales to mention backward compatibility in tiny text on the back of the packaging.
The point is so that no one sees the product with the new D&D logo on it and says "durrr...these tiles are 4th edition tiles. I can't buy them for my 3rd edition game, cuz they won't work." Yes, WotC is interested in selling games even to people who can't find their noses without a map.