honestly day trade is so random in term of profitability, nobody can guarantee whether you gonna lose your money or make profit, it is at the end of the day comes down to statistic and as of now 90% of trader are losing money, doesn't mean all losing money, if you got the edge you might become the remaining 10% who is profitable.
basically it depends on you and your trading ability, like any other activity, even arbitrage has chance of losing, doesn't mean everybody is losing though.
I agree with your sir, day trade is risky, it's completely uncertain way especially in day trading, but long term trading is profitable if will show patient, trading ability is everything in trading, who are experienced in trading, possible to make profits in day trading, but no guarantee about consistency even experienced traders.
Im a day trader and its easier to make analyze the market with the higher time frame because there's a confirmation that depends at the same time with the availability of the trader, I guess its riskier to trade with a lower time frame because the market is so volatile just simple market changes gives a huge impact on the price and of course you cannot skip just a blink of an eye to make trade on this. Instead in a higher time frame, you can easily make another execution where to entry and exit strategy.