I can't find anyone fighting against this notion. “Everyone is in sales” is toxic and advocates putting more than the job's duties on certain people.
We don't say “everyone codes” and expect sales people to just figure it out. I thought I could google these words and find people lambasting its usage (which has been prevalent at every tech company I've been at) but all I find are shills.
I know its probably a relatively minor concern and perhaps specific to “cushy” tech jobs, but its bizarre that I've never heard anyone challenge this.