Sometimes people mean "markets" when they say capitalism. Sometimes they mean the existence of really high wealth inequality. Sometimes they're using Marx's original definition about the means of production.

In the first case, I see no alternatives, and so am for it. In the second case, I'm against it. The third requires more discussion about how ownership should be structured, and which things count as means of production before I can even decide. Using a term that could be any of them just leads to confusion.