I think their logic is 3 fold:

1) Everyone benefits greatly from collaboration across companies and researchers at univiersities 2) There is a lot of value for google (and everyone else) as a company to show their achievements for many reasons, such as attacting talent, partners and so on. 3) And lastly, they don't expect the secrecy of their research to accomplish much, i.e. someone might re-discover similar results not that far into the future

Nlp tasks are not solved yet and without this collaboration between big corporations progress would be far slower, even for Google. For example a chinese student has outperformed and obscoleted BERT (the Google best Nlp model) with XLnet. Conversely XLnet wouldn't have existed without the BERT architecture

So is Baidu.

The whole industry benefits from this sharing of knowledge.

Also, the best aren't going to work where they can't publish.