I can tell you exactly how a progressive argues:
1) Talking points
2) misdirection (change the subject)
3) ad hominem attacks
4) cry RACISM.
Sometimes when I'm really bored I argue with leftist and Islamist anti-semites on YouTube. Your breakdown is spot on, though often they don't even bother with misdirection or cries of racism.
This is the sequence on YouTube:
1) Ugly anti-American and/or anti-Jewish post by "compassionate" "liberal".
2) I post a polite rebuttal with inconvenient facts.
3)They respond by hurling insults and profanities, then change to a different question to side step the facts.
4) I point out that they went ad hominem and changed the subject because they could not answer my rebuttal.
3) They leave the thread permanently (sometimes after repeating step 3 a few times).
After dozens of these encounters, never, literally not once, has a leftist/Islamist ever attempted to actually address the facts.