I'd add an asterisk to this, in that there's more than one kind of experience. This forum is also "actual interaction"; I don't think you can get away from that one. I don't think it's appropriate to try to discredit someone for being unwilling to pursue a face-to-face encounter with a person who has acted in a disparaging, abusive or arrogant manner in this forum. I'd call that instead making an intelligent decision.
I don't think it's appropriate to try to discredit someone for being unwilling to pursue *any* face-to-face encounter. Life is short. Training time and travel budgets are limited, and we all have to pick and choose.
But that cuts both ways. If you haven't seen someone, you're not really qualified to talk about what they can or can't do. (Something to especially keep in mind when discussing people who are now dead.) If no one has seen you, then no one can corroborate your own claims.
Along the same lines, it might be helpful to remember that writing ability has little or no relationship to any physical skill. Ability (or inability) to be articulate on internet forums implies nothing whatsoever about a person's martial ability (or lack thereof).