Netguard is open source (with a license not supported on iOS: https://github.com/M66B/NetGuard), so there is no reason to use a build that shows ads. Alternatively, as I said earlier, there are multiple firewall apps you could use that don't require root.
The weird thing is that you went out of your way to research to find a misleading quote when the page itself points out why the quote is misleading and that the app is open source (negating your ads claim earlier).
It has to route traffic through a local VPN to drop the traffic. Doesn't play well with other VPNs for this reason. Real firewalls need root. The VPN trick is a hack to get around that while still providing some of that functionality. Yes, you could edit the source code and compile it yourself every time it updates to remove the ads, but I think that's a little much to expect.
Ultimately this is functionality users should have access to by default without needing to resort to hacks and ad-filled workarounds.
> Netguard also injects ads in your traffic (or at least did) https://imgur.com/a/2YG7Q
Netguard is open source (with a license not supported on iOS: https://github.com/M66B/NetGuard), so there is no reason to use a build that shows ads. Alternatively, as I said earlier, there are multiple firewall apps you could use that don't require root.