I don't know how is why! (And if I learned, then my coworkers wouldn't know how, so until I got everyone else on board, I would be making the bed only to have them jump all over it again.)

Don't tell me to hunt down random third-party tools that none of my coworkers has heard of, that I have to convince them to adopt, and which each solve a little (usually overlapping) bit of the problem so I have to run all of them in series. That way leads to madness, and horrible one-off UIs developed by people more concerned with their tool's special-snowflake analysis algorithm than its output.

Instead, ship an extensible, plugin-based linter with your language's toolchain (e.g. mix for Elixir, lein for Clojure, etc.) Make its output beautiful. Write one or two simple plugins, and make installing lint-plugins as simple as adding something to the project's dependency file. Then I (and everyone else) will use this stuff.