No, Roth TSP/401k would still be a thing. It's just saying you can't convert after tax monies into a Roth IRA. This would mean most of us "rich" guys wouldn't be able to contribute to our Roth IRAs via the "back-door" or "mega back-door," like we do now. It's simply a money grab by the dems...something we've all known they've wanted to do for a long time.
A lot of us Delta guys (not sure what other companies have the option) use this to stuff our Roth IRAs to the gills. As an example, last year I used the "mega-back door roth," to convert 30k into my Roth IRA and was still able to contribute 6k into a traditional IRA (after tax), the convert that into my Roth IRA. So even though I made too much to directly contribute to my Roth IRA, I was still able to put 36k into it. That option would go away. Not the end of the world, but certainly a loss in a very nice benefit.
This is just the start of what they really want to do, because us rich guys are so greedy and "we didn't earn that." Means testing SS, eventual taxing of our currently "tax-free" Roth TSP/IRAs will likely be the next things in their sites. I'm certainly not planning on getting SS as part of my retirement plan, if it's there, cool more beer money.
If that still doesn't make sense, check this out. It's different than the standard back-door roth.