they're removing the caps so you can exceed the "limit" without being charged a few or artificially throttled back.
however, due to increased usage, the internet is indeed slower and less reliable for everyone.
streaming services like netflix are helping by lowering the quality of streaming to reduce the burden on the internet.
but my own experience and that of my work colleagues as well as countless internet stories attest to more interruptions, lower quality connections, slower response time, etc.
what may be a "lie" is whether or not (in normal times) it's specifically usage beyond 1tb that cause the problems. with covid-19, the problem is that many more people are using the internet quite a bit more, but likely many are still under the 1tb threshold. more likely, the 1tb threshold is there not merely to cut back total traffic, but because those people might be the most readily willing to accept a higher fee.
(i use optimum, not comcast, but the issues are the same).