Nonsense, I grew up in the Middle East and it was regularly above 120F during the summer. Just wear a hat and make sure you have water. You’re making it sound like you immediately die.
I grew up in Israel and 40c (104F) was an unusually hot summer day (you'd get a few days like that per summer, maybe more now due to climate change). More common summer highs were around 30-35c.
EDIT: I underestimated how much hotter the Arabian Peninsula is compared to the Levant - a quick look via google maps puts Doha at 39c right now (at 9am!), while Jerusalem, Damascus & Cairo are at 22c, 24c and 27c respectively!
If you grow up in the area surrounded by people who know the area, you'll do fine.
If you're casually wandering into an area like that coming from San Francisco or London expecting a fun weekend, you may very well pass out or worse.