Because, unlike Meta and Alphabet of the time, they were the first to give us access to this secret technology. They threw open the doors and the other guys had to follow, and Meta eventually went farther. But they opened the doors. Seems fine to me.
OpenAI was most certainly not the first organization to develop (or distribute) an LLM model:
https://github.com/google-research/bert
https://arxiv.org/abs/1810.04805
Failing that, Seq2seq predates OpenAI's incorporation:
https://google.github.io/seq2seq/