Woah friend, that right there is a loaded question.
What is the point in doing something in a similar manner to someone else? What do you define as a copycat? Is this someone with a similar formula or someone who note for note copies another persons work? Cause if it's the latter than I don't know what to tell ya. It works...sometimes? Being a blatant copy of someone successful doesn't usually yield good results.
That's also a loaded statement. I get the feeling you're trying to make people mad more than anything, but I'll humor you and answer with this. While I'm not trying to blatantly copy other channels, I am influenced by others. A lot of people are currently in the gaming scene. Whether you're doing reviews, let's plays, and or gaming news/commentaries. A lot of people do this for the audience and interaction. The reason you find a lot of people "Copy" each other is because we learn from success. Methods bigger channels and inspirations use become standards. Posting daily is standard for most popular LP channels, Talking about certain topics that are trending is standard for science shows, etc.
Doing YouTube is about staying on top of trends. This means making content that is similar. The hard part is standing out. This is where your "copycat" channels come from. The channels that whether they're actively trying to copy someone's style or not are producing content for people.
Wearing your inspiration on your sleeve is a tricky thing because you want to show people what you like, and what you follow, without seeming like a "copycat".
Your style is formed around the content you consume. A collection of things that you enjoy being mashed together into something you can call your own.
People do things in certain ways, because it's proven to work. It's a matter of changing it up so you don't look the same.