Starting with a large capital without sufficient knowledge and skills in trading increases the risk of large losses as well as profits. If a new trader does not know enough about market fluctuations, stop-loss, risk-reward, then a large capital can increase the amount of losses instead of solving his problems. Trading does not become safe just by starting with a small capital. Trading risks still exist. Getting good results for a certain period of time does not mean that the same results will be obtained in the future. Therefore, it may be more important to start small and gain experience than to start trading with a large capital before developing skills.
You say that trading is risky and you still want person to be starting small in trading, what make you think that you wouldn't loose even when you start small. So if you like use large capital to trade or if you like use small capital, losses can still happen, it cannot be avoided. Even those person that have plenty experience in trading still use to loose money anyhow.
This is why it is not a good choice to trade. Or it should be reduced down to the barest minimum. Person can just ongoingly invest for a long time using discretionary income and then quit obsessing over trading. Doing that will help the person to grow their wealth over the years.