That's all well and good - and many people realise and accept this - but the degree to which you're the product can clearly vary wildly. That's the real issue.
Of course it varies. It's up to you to decide/deduce/infer what the "cost" of using a free service likely is. Understanding that there IS a cost is really the first step, one which a good portion of the population seems to not understand.
To be fair Unroll.me shows you ads in their emails to you so a user may think thats how they monetise and be ok with that. Its another thing altogether when the company sells all of your email data directly to buyers.