Few sliders turn up because they are treated like " Lepper's " these day's, and that attitude has drifted into the classic classes as well.
I admit that in the old days the riding style of an MX'er and a Slider were totally different, after watching the current stars on their modern MXer's, they now ride much the same as someone on a slider.
The longer they are ostracized the harder it will be to get them back.
Sliders take a lot more development to get them competitive and if someone is prepared to go down that track then good luck to them because when they get it right they are spectacular.
After Billy Mac's grandson end for ended his modern 450 at the national titles in Canberra last year, Billy's comment was, if that was a Hagon you'd chuck it in the bin, that's just another part of the modern equation, durability.
Honestly, I don't know what all the fuss is about, if it's a legal and more importantly a safe bike, let em race.