Backlink outreach pricelist response...?

So i was doing some backlink outreach for a web app of mine. The app is in the Irish tourism niche.

I emailed a high Domain Authority site that ranks well on Google and asked them whether they'd be interested in linking back to me...

I get a return email from them listing their backlink prices.

I sent a short email response, asking them whether they knew that Google often de-indexes websites that sell backlinks. At least it's prohibited in Google's webmaster guidelines.

What would you have done in this situation? Was I right to point this out? Or is this just how the game is played?