The way the pay-per-click machine works, is you pay like 3$ for 'hotels in amsterdam', their average (public info) commission is 15%. Looking at booking.com/amsterdam you can see vague idea about average price, lets say most bookings are 2 nights, then you can get ballpark average reservation of around 200$, 15% of that is 30$. So for each room they sell they can buy 10 clicks on 'hotels in amsterdam'.

This is super ballpark estimates, could be order of magnitude different, but the idea is that there is enormous incentive to push people to book, its the same as the example in the article, pushing people to buy. Purely because the pay-per-click is so expensive, you need ROI > 1 to survive.

Those companies are in survivor mode, and anything that is even remotely legal, or can be defended in court, is allowed and encouraged.

Thing like 70% off on pair of shoes, that just had their price increased by 90% for 1 minute, just so there was a record in the database that they actually had higher price, nobody cares that they never sold at the high price.

Companies constantly push the legal boundary.