The ad is from the Israeli real estate company Harey Zahav. They posted this on their Instagram account. After criticism and backlash they claimed it was posted as a joke.
The Norwegian journalist collaborative fact checking service Faktisk.no has done a deep dive on this ad with a lot of detail if you want to check it out. You can read it using google translate (or similar tools) you are interested.
https://www.faktisk.no/artikler/jdplr/kraftige-reaksjoner-etter-spok-om-boligprosjekt-i-gaza
Some interesting facts from the article: the ad text says they are working to prepare for a return to Gush Katif, an earlier Israeli settlement in Gaza. The company is responsible for the development of settlements on the West Bank. The owner of the company lives in Moscow and seems to be an oligarch.
So based on the info in the linked in the article the ad is very real. And while the company behind it claims it was all a joke, that does seem a lot like damage control.
The goal of pasteurization is to kill of harmful pathogens. If you do this early and package and store the milk in the right conditions it can be stable and safe for a long time.
If you don’t pasteurize the milk and leave it for a long time, pathogens in the milk, such as bacteria, can potentially produce toxins. Boiling it at that point might not help, no, as it kills the bacteria, but can leave behind the toxins.
So pasteurization is very effective if done early, but you can’t do whatever you want to the milk and then pasteurize it right before using it and everything is good.