If you would like to allow comments but just remove the “leave a comment” link on the main page, then consider adding the following code to your CSS stylesheet:
/*
* Hide the "Leave a comment" link on the front page.
*/
.comments-link {
display: none;
}
If you’re using Jetpack, add this under Appearance > Edit CSS
so that your changes persist between theme updates.
As a general note, it’s my opinion that the “Leave a comment” link doesn’t make much sense for blogs that display excerpts on the main page. There’s not much reason to provide a link to the comment field before the reader has had a chance to read the post. Given that this is a relatively common use-case, it’s surprising that the theme bakes in that link and doesn’t provide a convenient way to remove it without disabling comments entirely, which is fairly extreme.