Like with pronouns, one could choose two options rather than just one.

The options would be something like:

• whole
• 2%
• 1%
• skim
• lactose-free
• chocolate
• strawberry
• buttermilk
• kefir
• kumis
• infant formula
• mare
• goat
• cow
• human (default option)
• almond
• cashew
• coconut
• hazelnut
• oat
• rice
• soy
• pea
• hemp
• 🎶︎ no milk today 🎶︎

And any other options we can think of.

The sole and exclusive point of mandating preferred milk type would be such that people could comment things like

SKIM!

to make fun of any carnists who choose to out themselves using this feature.