SQL is pronounced ‘Sequel’ because it was originaly SEQUEL.

SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd[12] in the early 1970s.[13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM’s original quasirelational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s.[13]

en.wikipedia.org/wiki/SQL

It then later changed, evolved, and changed from being an acronym into an initialism, kind of, sort of, mostly for people who are unaware of the etymology.

Thanks for making the comment I came to make. I imagine being older and remembering SQL as a new-ish thing really helped cement this, but when I started programming professionally for an enterprise, literally everyone pronounced it like this. I can see how and why it makes little sense to younger people.