I don't know what version of the DS-5535 you got, but the social media question they ask is:
"Please provide your unique user name for any websites or applications you have used to create or share
content (photos, videos, status updates, etc.) as part of a public profile within the last five (5) years."
So, I personally wouldn't worry about some old/private/deactivated accounts.
FWIW, some immigration attorneys even question whether there is any serious vetting and investigation that they do following the DS-5535 submission, they wouldn't give clearances just to avoid dealing with lawsuits if that was the case. Just an opinion. This process is a blackhole and I am just guessing here.