I just saw that myself, I do not recall reading that when I bought it some months ago.
It will do 1080p, however, I don't normally send 1080p since it is a kitchen TV and my main display is a 720p projector, hell the wife watches SD cooking channels on it! So it may be better for you to pick one that says it will do 1080p. It just may be that 35' is beyond the spec for HDMI, so that is their disclaimer if it does not work. I have my cable plugged into a Matrix the claims it will allow longer runs than 25'. I would suggest you do a bit more research on the cable, there is an All things HDMI forum on this site down near the end of the main list.
Oh, the reason I went with that flat cable was I needed to make a very tight bend to plug in to the side of the TV. Most of the other High Speed cables I have do not bend that sharply. The flat one will bend completely back on itself.