What? Why?

As far as I understood - There are two entities - WordPress and WP Engine Matt Mullenweg (WordPress guy) says WP Engine has not contributed to the WordPress open source core for the amount of business WP Engine has done over the years. WP Engine responded that their contributions are in the form of sponsorships and running events and such. There might be more to the arguments, I am not too sure right now. Matt said all this stuff live in a conference in his speech, he even called WP Engine a "cancer" within the WordPress ecosystem.

They are publicly fighting amongst themselves? Weird!