Either human is a special category with special privileges or it isn’t. If it isn’t, the entire argument is pointless. If it is, expanding the definition expands those privileges, and some are zero sum. As a real, current example, FEMA uses disaster funds to cover pet expenses for affected families. Since those funds are finite, some privileges reserved for humans are lost. Maybe paying for home damages. Maybe flood insurance rates go up. Any number of things, because pets were considered important enough to warrant federal funds.

It’s possible it’s the right call, but it’s definitely a call.

Source: https://www.avma.org/pets-act-faq

If you're talking about humans being a special category in the legal sense, then that ship sailed away thousands of years ago when we started defining Legal Personhood, no?

https://en.wikipedia.org/wiki/Legal_person