Let them think about that since maybe they didn't experience yet a huge defeat on their investment made with those altcoins that's why they criticize you for now. But once they lose all their money with those alts then provably they would remember those people say that investment on altcoins is just a waste money and time for them. If they just invest it on bitcoin and accumulate for many years they could just earn a lot more compare to the losses they get.
Realization comes late and if they are hard headed and criticize you for giving such good word or advise then let them learn a lesson on hard way that he could remember his mistake for all things he do. They are just overwhelmed with the hype brought up with other people short gained result but for sure they would able to realize that altcoin investment is not really sustainable.
It isn't just learning the hard way, it would have been more better to learn from other people mistakes but perhaps it is always advisable for anyone who can not resist the urge of getting involved with other coins other than Bitcoin not to do more than 10 % size of your Bitcoin in to other coins, so as to give your Bitcoin investment all the necessary attention needed as regards to ensuring working towards achieving a successful Bitcoin investment which should be the motivation for every investor with a proper planning. Alot of people are just being skeptical about understanding the Bitcoin as the chief executive coin of other coins hence procrastinates given Bitcoin the respect that they are ought to.
Brand new investor does not need to think about shitcoins but only bitcoin so that he does not distract himself from his bitcoin target, because bitcoin is only the coin that is worth investing in, since it has the potential to increase your wealth in future as long as you invest in a long term and accumulate a good size of bitcoin overtime.
They should never make shitcoin as an good investment to choose, but rather avoid this since we know how bad the chance for people to lose on those crypto since rug pull are most likely will happen especially if they are into new tokens which is really so risky for them to take.
Some think about that if they don't take a risk they don't earn, But if they just think about what they do and focus on how they can accumulate then provably that they can get more better insights and will just decide to accumulate more and execute well the DCA method especially if they see that bitcoin chance for its price to rise is so high.
Good choice of investment together with proper execution of strategy will bring something good to them in future.