Yep, you're reading that correctly: the Tampa Bay Buccaneers will not re-sign their young players, at least not this offseason. Not unless the CBA drastically changes some rules.
The Bucs have a young roster with several up-and-coming stars, and they have a lot of cap space. This means the Tampa Bay Buccaneers will have to spend to meet the salary floor, and they have the perfect people to spend it on: young players. Except, they can't.
In the last CBA, teams weren't allowed to renegotiate rookie contracts during the first two years of that player's contract. It's unlikely that this rule will change in a new CBA. In fact, back in February the NFL's proposal included provisions to expand the non-negotiation window to three years. Under these rules the Buccaneers wouldn't even be able to extend their rookies, even if they wanted to.
In addition to that, a lot of these young stars have only one year of high-quality performance, and that is simply not enough to be rewarded with immediate contract extensions, especially not when these players are still under contract for three or four more years. Consistent performance over multiple years will earn them new contracts, but it's early now. Even for Josh Freeman, who has three more years left on a fairly lucrative contract.
However, this could lead the Bucs to be a little careful with their spending, despite having so much cap room. This to make sure they will have enough room to re-sign their young stars in future years. John Clayton even names the Bucs as one of the teams most hurt by the new projected salary cap and floor, though I think that's a real stretch. Still, the Bucs may choose to be judicious with their money for now, especially so because they've said that they want to build this team through the draft and by extending their own players.