This isn't 35 years ago.
It's such a simple process to filter out defensive TD/special teams when looking at stats like that.
Same with FBS v. FCS games.
Websites need to do better and make it clear.
As you point out - it does makes a difference.
I'd even go so far as not counting extra points against a D.
They really only gave up 6pts - not 7. Put that on the special teams.
Maybe these have more refined stats available but behind paywalls.
A good stat would be "expected points given up" and factor in drive starting position.
For example - a team gets a fumble return to our 20 yard line.
If the defense then holds to a FG as opposed to a TD - is it really that bad?