It seems to me they don't know what "one-liner" means. It means 1 (one) line, not one paragraph. The following would be examples of one-liners:
The facts amount to a damning case against the president.
No, the case against Trump is built on suspicions, insinuations, hearsay, and various irrelevancies.
We have established that bribery (or attempted bribery) occurred.
No, the hearings didn't establish bribery/extortion/whatever your focus group thinks you should call it..
The case against Trump is airtight.
No, actually the central claim, that Trump withheld aid for the sole purpose of hurting a potential political opponent, gets more and more ridiculous the more you think about it.
The president did this for his own benefit.
It is irrelevant that investigations might benefit Trump if there was reason to believe that there was corruption in Ukraine, Burisma, and yes, even if it involved the Bidens.
There is widespread public support for impeachment and removal from office.
If that were true, democrats would be moving forward with it without reservation.
Republicans don't accept the impeachment because they live in a news bubble.
No, data shows that liberals live in a news bubble, and republicans and moderates do not.
Also, I find it hilarious that the readers of these left-wing sites need their half-assed, poorly formed "arguments" spoon fed to them.