They're not communication-averse. They're just not stupid.

The human on the other end is an experienced, well-paid, highly incentivized sales specialist, whose job is, to put it bluntly, to screw you over as much as they possibly can. Talking to them means entering negotiations on their terms. Unless you're well-versed in dealing with salespeople, they will play you like a fiddle. The business of their company relies on clients clueless enough, or big enough to not be sensitive to losses at this scale. It's plain stupid to engage from a severely disadvantaged position if you have any alternative available.

This applies doubly if they're cold-calling you. They are the hunter searching for easy marks. You are caught by surprise and entirely unprepared for the confrontation. The right thing to do is to stay quiet and let them go chase someone else.