Non-Q and R: how would you respond?

From time to time I receive emails like this one:

Subject: Blasphemy is More like it
You try to show God’s love in your lifestyle, but deny them the truth.

That’s it, unedited and in its entirety.
As I read this, I thought back to times in my life when I might have sent an email like this to someone. I remember what it felt like – the need to pronounce judgment on people whom I saw as in error, the feeling of being unfaithful if I didn’t speak out and name them as a liberal, a heretic, a hypocrite, whatever. I wonder now if my need to condemn others was a projection of some subconscious insecurity of my own, but then, on a conscious level, the only thing I felt was that I was faithfully standing for the truth.
Of course, I probably wouldn’t have had the good sense to keep my message as short and to the point as this respondent. I probably would have gone on for page after page, specifying the errors and failures of my “target” audience. And I probably wouldn’t have had the good sense to at least acknowledge something good in “the other” either – in this case, “you try to show God’s love in your lifestyle.” So I feel a certain respect for the person who wrote this. He is farther along than I probably was at his age, and life has a way of keeping us all learning, even when we think we’ve already learned enough to render judgment on others. Some of the people I wrote off earlier in my life I later learned had a lot to teach me, and now I thank God for them.
The comment raises an interesting question, perhaps the flip side of this one: If someone is trying to proclaim the truth, but does so without showing God’s love in his or her dealings with others, how should we respond? I’d love to see some responses over at my facebook page.