Chill a little, if he doesn't want to fix it he doesn't have to, it's his mod. Obviously there will be work arounds and it’s rude to be palmed off with an excuse. At the same time this is a large mod that takes a lot of work. Few people have the time or motivation to get around to fixing everything in a mod of this size. Especially when it doesn’t connect to the core of what they want to build.
If the mod is really important to you, try making a fix yourself. The license allows you to make and post modifications with credit. You could also find another mod that does what you want better.
It's not the fact that he won't "fix" the problem that made me angry. It's the entire attitude of "you have to play the game/mod the way I say" that does it. Instead of just posting a warning that the combat mechanics mod will nerf/break certain enemies in the mod, he just makes it an incompatibility (which is very annoying to change when playing with friends.) The mod author hiding behind the excuse of "it's a feature of the game engine" as cover for it just made me feel even worse. My friends and I have just removed the mod from the mod pack instead wasting the 60 hours of playtime before heading to Nauvis. Nothing in the mod is worth the 60 or so hours of playtime that would be wasted after already spending almost 20 hours trying to make a base on Nauvis after finding out that evolution starts increasing the moment the game does even if you start on another planet. 20 hours of putting out constant fires and broken turrets because large spitters are blowing up our base. It's our first time playing with Rampant at all. Finding out that spitters who normally target walls first, instead walk up and start shooting turrets and inserters is a frustrating. We tried to find a mod to help, only to find out that it has been made incompatible.
I know that's a giant wall of text, but I'm not posting to just make the mod authors day worse. I just don't like people hiding behind excuses instead of just being honest about their opinions. If a person is thin skinned enough that some people getting angry that you're gatekeeping how other's play your mod, then maybe you're the problem. Just let people play how they want, it doesn't hurt anyone.