I guess the devil is in the detail.
If such a function was implemented (say) as Al suggests “The PST should offer to properly format any thumb drive connected to it. Format y/n?” then can you imagine the support calls you’d get?
“My son gave me a USB stick with music on it - I plugged it in and it asked me a question. I thought it was asking me if I wanted to play from it so I said yes. And now my music is all gone!” etc…
If you bury the function in a menu system then you make it difficult for the very users you are trying to help.
I know you are looking at just this one issue from an end-user point of view but as someone who has worked in IT for 40 years and specialised in Human Interface Design for at least ten of them, I can tell you that vendors have to balance a number of compromises in the areas of ease-of-use, cost (development and maintenance) and keeping their customers safe from themselves and external sources.
And the dearth of devices that have read-only access to memory cards that offer the ability to format those cards tends to indicate that vendors don’t consider that offering a format function passes the risk/reward threshold.
In my little universe I have 2 x printers that allow printing of docs and images from a connected USB stick. Neither allow me to format the stick.
Then there’s the PST which similarly does not allow formatting a connected stick.
Of course there might be exceptions. There always are