No, I reckon the supplier is just following the trend, similar to the use of the phrase "pregnant people." Respectfully (or maybe not) I think your considered reply is the bollocks our girl Bessie was born without. :-)Just easier from a programming perspective. You just know if someone’s entered the sex wrong on their database and they send an email to a male cat saying “her” someone will kick up a fuss.
The thing is though, using “their” has always been acceptable English in this context. I bet you use the phrase “they should have known better” when referring to an individual all the time but it’s the same concept and isn’t something related to gender identity at all.