But I could make the same argument as to why my "strategy" playing slots or roulette is good, but in reality it just means I've gotten really lucky, and I might wipe out all my earnings in the span of an hour if that luck suddenly turns. That's not to say there aren't legitimately profitable trading strategies—"you can't beat the market" is, strictly speaking, demonstrably false—but "buy stocks of companies I like" is not one of those, and is entirely equivalent to gambling.
Anyway, I have little desire to repeat the same old arguments, nor convince anyone else. However, one might consider the differences between a slot machine (which tells you up front that you will lose money in the long term, and has no stop orders) and trading equities. Or don’t, matters little to me because I have no argument to win.
If you take a few million people and have them invest in put or call options every year, you're still going to have some streaky winners after 20 years. Very few individual investors I have talked to have convinced me they are even tracking results well enough to back their claims of outperformance.
Not OP, but the simple answer is: “because my returns over the years prove that I can.” I’ve heard this question enough times over the years that I usually just ignore such silly questions and go back to buying deep-in-the-money AAPL calls. Conversely, if it makes one feel better, continue to tell yourself individuals can’t beat the market (which is mostly true).