
Bruce Perens has lost the plot and for love of $DEITY, can we please stop calling it "open source"? It is "free software" as in freedom. It has nothing to do directly with the ability to see the source code. Freedom is baked in. That was the *whole* point of the free software movement.
Whatever the truth about the trademark claims (honestly I don't care, it is for them to sort out in the courts), WP Engine are for the most part selling hosting, which is infrastructure. If I buy a hammer and use it to make furniture, I have no legal nor moral obligation to contribute to the development of hammer technology: I am selling my labours and the service that I am providing to my customers.
If my selling of furniture is immensely successful then that's great for me and nothing to do with hammer manufacturers. If the makers of hammers have a problem with that, then they can f*ck off.