How do you know they're trying to sell you something without even reading the email?
Your question was "Do you read/answer cold outreaches then? Why?" which doesn't make much sense. For me, and I imagine the same applies for most people:
1. You read until you find a clue that its content is not of interestt. Usually the email subject doesn't say much.
2. You only reply if you need.
Cold outreach are genuine emails that covers colleagues, new clients, job opportunities, someone reaching out to collaborate, etc. How you deal with it depends on your profile and who you've given your email address to. Personally, I have many email addresses, for some I don't even check my inbox.
