There are people who have broken free from bondage to rules and regulations into a genuine walk with God. This is cause for great rejoicing. And the cautions they have about legalism are usually worth listening to, tied in as they are to the reality of Christ living in us.
There are other people, though, who proclaim their freedom from legalism, yet something still seems amiss. They drone on and on about the evils of this rule and that rule. They are full of critiques (and no charity) for this group and that other group. They're happy--zealous--to exhibit their freedom to do X, Y, and Z. And if you (for whatever reason) happen not to do X, Y, and Z, well, you must be one of those judgmental legalists, too.
I've always had trouble putting my finger on exactly what was wrong. What they said about legalism might be true, and no one could doubt their antipathy for it, but why did their words and actions still seem so . . . legalistic?
I think I finally hit on it. The error of legalism is thinking that by our own actions and observance of rules we can gain justification, sanctification, or the fruit of the Spirit. Observing rules does not make us any closer to God. But neither does breaking rules make us any closer to God. The error of what I might call "anti-legalism" is thinking (subconsciously, I think) that freedom in Christ is found by going out and breaking whatever particular set of rules you were brought up to observe. But the focus is still on the rules, not on Christ.
Isn't that what Paul kept trying to warn us about? "Neither circumcision availeth anything, nor uncircumcision availeth anything, but a new creature." If you're still obsessing about the rules, whether you're for or agin them, you're still missing the boat.
Lark News has a report that shows where this type of thinking leads. ;-)