The cost of epipens affects someone's ability to not die. Whether WP Engine contributes back to WordPress enough does not.
In fact, Mullenweg says WP Engine does contribute back, but not enough, and tries to justify it by saying they've "hacked up" WordPress. The latter statement has no legs to stand on (at least without real evidence). How much is enough? Should WP Engine be fixing bugs that don't affect their customers? Exerting influence by throwing contributors at wordpress to make upstream improvements that benefit WP Engine customers? I suspect if WP Engine did what Mullenweg is indirectly demanding, we'd get a "no not like that!" post.
The cost of epipens affects someone's ability to not die. Whether WP Engine contributes back to WordPress enough does not.
My example also cited two non-life threatening issues, and discussed legal vs morality.
You have not addressed this point, so I'll be more direct about it. Doing something legal doesn't make it OK. In fact doing something legal does not imply right or wrong.