I didn't read it as him suggesting that he'd stop writing, just that he'd make a conscious effort to stop defending himself from online attacks. I agree that it would be terrible if he quit writing his essays.
I was going to expand this thought but when I thought what some of the responses might be, I thought, "Life is too short!" and left it as is :)
An essay is partly a matter of working out one's thoughts on some matter. But _posting_ an essay advances some point of view with a supporting argument, attacking the beliefs of others (e.g. Sanders was not named by pg, but could have been). That seems to be _arguing_ just as much as the additional step of responding to one's critics.
I suppose what makes the latter wearying is that it's hard to hear attacks on you personally, and tedious to respond to attacks which are loud but bad. But it still seems that we should (and usually do) value those who engage with their high quality critics.