Science

This article doesn't actually mention the values of the temperatures (probably to cover relieve themselves of the responsibility of those details) so I'll go to their first link, the theHill.com one. They don't directly give a value in their text either...

Reading that, the exact same thing is happening as that twitter screenshot thread with the map of the southern US color coded for temperatures.

Basically, wet bulb globe temperature is being conflated with wet bulb temperature. Globe is in the sun, the other is not. The thehill.com source uses a chart and description for globe, doesn't mention the word globe anywhere, then says you can't survive more than 35C with a link to a study. That 35C/88F is the limit for a wet bulb temperature, not wet bulb globe temperature. Obviously measuring something in the sun is going to give a higher number than in the shade. You can't say "it's this temperature" referencing wet bulb globe and also say "you couldn't survive that temperature" using the "survivability" limit of wet bulb without any sort of qualification/clarification as to the distinction. Obviously it's hotter in the sun. If that same temperature is reached in the shade it's that much hotter in the sun.

Sure, we're all facing extreme climate apocalypse, but this is annoying that the terms are being used as the same thing, and I'd argue detrimental to the cause. When these things are incorrect, it's just more ammunition for deniers and doubters to point at to justify their continued intentional ignorance.