Making comparisons can be both good and bad. As long as they are constructive in some form then you shouldn't be telling people to stop making comparisons.
This game hasn't exactly 'redesigned the wheel' for zombie games. It added the Horde mechanic which i love but other than that... it isn't some unique never before seen game.
Drawing comparisons to similar games has a very real point. Unless the individual is just being toxic the point is to try and make the game even better than it is now.
The WWZ Team should be comparing themselves to games that are still going strong and that have a very high player crossover i would imagine. It isn't to copy but to see where the other may have faltered, what strategies worked for them and to take the lessons learned from other games and studios and turn that experience into something positive for their own game. I'm not saying you can learn everything you need to improve or build your game further by drawing comparisons. But it is incredible helpful to look into past games that share the genre and players and see how you can improve and outdo everyone else.
Look at Anthem, they repeated all the mistakes of the games before them because they were unwilling to draw comparisons between their game and the competing games other developers made.
TLDR: There is a very real point in comparisons. Just because you don't get it don't discourage others from bringing forth ideas that may make the game even better in the long run while keeping it "it's own thing".