Part of the polarisation is their marketing - attracts some people, and repels others. Part of it is the huge diversity of stuff they sell. Some is good, some is great, some is great value, and some is poor value. Some of their swords are historically very inaccurate, some are pretty good. Some of their swords are clunky overweight lumps, some are underweight, some are the best-handling replicas of their type (though sometimes still not so good - just better than the competition). So different people can have very different Cold Steel experiences, depending on what they buy.
Some of their swords suffered from defects (like fragile threaded rods holding pommels on) in their early versions, and that reputation lingers. Supposedly their early model katanas were hideously ill-balanced and overweight. While they're mainstream enough these days, their early reputation still lingers.
Their katanas are made by Huanuo who do respectably good stuff (they also make most or all of Cold Steel's Chinese swords, and probably some of their European ones). The Warrior series sword are bottom-end Huanuo, but that's still fairly good. Huanuo also make the swords Dynasty Forge sells; DF have a bigger range of Huanuo stuff, quality-wise, from pretty much the same kind of thing as the CS ones, through to fancy (and expensive) versions.