It's perfectly reasonable to cringe at a $135K price tag. But if that's so onerous, why not spend a day compiling the source and setting it up for distribution on your servers? The answer is that you (or at least the hypothetical you) feel entitled to this software packaged how you want it with the features you want.
If you want to use Apache, use Apache. That's totally your right. Or you can fork NGINX and do whatever you want. It's even got a BSDish license to make that easy. You could even use the last version of the software that baked this feature into the standard distro. But you're using the official NGINX distro for a reason, and I don't see why the people who make it shouldn't demand a bunch of money for whatever that reason is.
To be clear, it's perfectly fine to say, "I don't think this is a good feature to put behind the paywall." I'm just balking at the whiny and entitled tone of the original post. "How dare they ask me to pay for the things I want!" If I were trying to monetize an open source project, per Jacques's comment above, this is exactly the kind of high-scale feature I'd target for that.