I think you need to confirm your email address to be able to make comments. Check your email inbox for the confirmation email from imgflip. It may be in your spam folder.
If that doesn't work, next step would be send an email to
[email protected] but based on my experience and your choice of username, I would not hold my breath waiting for a reply.
ONLY If you used a fake email to set up this account, use the arrow in the page upper right, go to settings, then edit settings. I think you can edit your primary email address, then hit update. Trying to help, but not 100 percent sure about the needed steps to enable your commenting. Hope to see you commenting soon.