I use the Jamstack to some extent at work (Gatsby and AWS Lambdas). I think it's an interesting technology stack with some excellent use cases (and a fair amount of hype).

I also use Wordpress for serveral small/mid sized personal and F&F blogs.

I don't think comparing the comment options in Wordpress to the comment options in Jamstack applications is fair. Wordpress is a complete CRM designed for blogs/modular websites. The Jamstack is a design pattern; it's not supposed to include the kitchen sink.

Like @qeternity mentioned, the A in Jamstack stands for APIs. The author only mentioned the ability to hosts comments in Wordpress (or another CRM). Why not roll your own comment system? Sure, that's extra work, but it's also very doable if you're building a Jamstack application (again, it's not a one-click solution -- Wordpress already exists for that).

> As a result, my own blog, which is a Jamstack site, doesn’t support comments! What do I do if I want feedback on a blog post? I add a link to a corresponding tweet, asking to add a comment there. I myself feel ashamed at this compromise, but given my site’s stack, I don’t see how I can solve it. I still like my blog as a Jamstack, though, because it’s fast, it’s free, and I create all the blog posts in Markdown using VSCode. But I can’t create a community!

I don't have a "free" solution for you. But you could use a storage option like Dynamo DB, create an AWS Lambda endpoing (with API gateway) to add/get comments, and return them as JSON to your Jamstack application. Boom. A comments system. Pricewise, it shouldn't go over the AWS free tier for Lambda. I could literally spin this up in an afternoon -- let's do it this weekend if you're in.