I don't see a problem with companies writing tutorials and OSS libraries to share with the community. If there is an economic incentive for documentation to be written and free software to be created then what's the problem really?
If the article is blatant self-promotion then I could see the problem with that and those articles don't get anywhere on HN/Reddit/etc so they won't rank well on Google either. But I've seen some high quality docs/libraries coming out of companies like that and it's a great thing.
The aren't responsible for developers doing poor implementations of JWT. And other developers equally have a voice such as the OP if they have a problem with the choice of technology they are promoting.