i assume that what you call pro traders are traders on desks in institutions. they never think in terms of capital, that is why percentages never mean anything to them. i think this is the weakness of these institutions not their strength. in quant hedge funds and ctas, who are in my opinion trhe real "pros", nobody will laugh about you when you are having fixed rules interms of percentages. i would admire your "pros" too much. it is a different story and there are many quite absurd things, like their decreased risk appetite at year end and year start. only due to the strange bonus payment usages there ...
Wouldn't you be the same way? I mean, the only thing they have at risk is their job. They have a call option on the bank's equity. If I trade that way, I blow up and have to scrape together another account. ND