In my opinion, this is an incredibly stupid design choice.

After being once caught by surprise, now I check carefully for a specified working temperature of at least 40 degrees Celsius, whenever I am buying any laptop or desktop computers.

This, for example, disqualifies all Gigabyte small computers. Moreover, any computer which does not specify explicitly the maximum working temperature must be automatically disqualified, because it is overwhelmingly likely that it has been designed for 35 degrees Celsius and not for any higher temperature.

Some computers are guaranteed to work normally up to 35 degrees Celsius and to work with reduced performance between 35 degrees Celsius and 40 degrees Celsius, for instance many Intel NUCs. This is perfectly OK.