This is no way disregards the difficulty of living with an actually severe case of ADHD but is not what most of these people are dealing with.
EDIT: many seem to have misunderstood what I mean by this. I’m not saying these people are only claiming to have ADHD to use it as an excuse. What I mean, is that they may very well do have, and they’re using it as an excuse. Mostly to themselves.
Lack of self-discipline is not doing what you know needs to be done and giving yourself excuses as to why this isn’t your fault but solely due to external reasons. It’s not taking personal responsibility and instead blaming the world for your issues. I can never afford a home because of capitalism. I can’t work out because of bad knees. I can’t get a girlfriend because I’m ugly.
If a person with no job or friends spends all their time inside smoking weed, playing video games, jerking off and then justifying this complete lack of function by telling themselves a story about how their mind is broken and there’s nothing they can do about it then I’d claim that more often than not there other reasons for that than just them having ADHD. I know because I’m that person.
At no point have I said ADHD doesn’t play a role in it but it’s always a combination of several factors of which some they have more control over than others.