Be cautious about “equality is simply socially constructed”

Do not make a very broad philosophical claim:

“There is no objective equality; societies simply construct whatever equality means.”

That would indeed require a larger theoretical discussion.

clarify that you mean something much more concrete:

Societies develop historically specific ideas about who counts as an equal person, and those ideas influence how legally equal people are actually treated.

That is not an extravagant philosophical claim.

It can be supported historically.

You can see it directly in Reconstruction:

the law changed;

slavery was abolished;

citizenship and voting rights were expanded;

but racial hierarchy did not disappear;

social resistance and segregation persisted.