I was looking for an option to disable confirmation for topic subscription and could not find it.
I think that for general forums the confirmation is somewhat annoying the members for the reason that if a member did select to subscribe, there is no reason for another step.
Much simpler to "send and forget"
Example of a mail that I got from your forum:
Thank you for subscribing. This is an automated response. We are glad to inform you that after confirmation you will get updates from - WP 4.7 compatibility.
Please click on link below to complete this step.
Confirm my subsription
I believe in streamlining and "Easy&Lazy" for the members and this extra step might drive them out to other forums...
If the box is not ticked, the member shouldn't get an activation email.
Maybe it's a bug?