No, it's not. It's saying that neither liberalism nor conservatism have everything right nor everything wrong. His argument is that some issues are ignored by both right and left, and while Christians can find common ground with both, they should not fully endorse either.
I agree with Mr. Alcorn. There's a lot of things where the Republican party is completely incompatible with Christian principles of social justice. At the same time, the Democratic party espouses principles antithetical to the moral norms clearly written in Scripture. That's why my loyalty is not to party or elected leaders, but to the Kingdom.
You are right in that the Kingdom is above labels such as "conservative" or "liberal".
However, that does make conservatives and liberals morally equivalent.
Simply stated, moral equivalence attacks start by finding something wrong with conservatives (not hard to do). They then proceed to claim that even if liberals are wrong on some things too, it doesn't matter because conservatives are also wrong on something. Hence, the two are morally equivalent.
Arguments like this are easy to make, and will always be possible as long as humans are sinners (which we all are).
But there is an antidote to the slippery slope of moral equivalence. If you recognize you are a sinner in need of salvation, you repent, and you ask for forgiveness, you have ceased to be morally equivalent to those who have not. Conservative Christians, generally speaking, have taken these steps. Liberals, generally speaking, have not.
Many liberals, in fact, insist that their sins are not sins at all. They have no intention of "repenting" for something they refuse to acknowledge is even wrong. Many of them have gone so far as to assert that there are no moral absolutes at all, only shades of gray.
Liberalism has long been non-Christian. But the typical liberal of today has gone even further, attacking Christians who believe in the truth of their religion as down right evil. Perhaps that is because we Christians know we are sinners ourselves, and we know that liberals are too.
I can easily see how a liberal who rejects his own sinful nature would object to those who consider him a sinner. A person like this might even consider people who call him a sinner "hateful". Such a person might strive to pass laws making it illegal to call their favorite sins a sin. Numerous contemporary examples of this come to mind...
We live in a time when right is wrong, and wrong is right. A great moral battle rages. The sides are not morally equivalent, even though the people on both sides are sinners. I know which side I am on, and I hope you do too.
This article, and your post, could be interpreted as supporting the fundamental "moral equivalence" argument. It is a slippery slope that leads to disaster. I hope that was not your intent.