This is correct for newbies. For experienced users no. Investing in the right altcoin will prove to be much better than investing in bitcoin (in the future).
So what happens when they buy in at $190 and it dips to $150 like it will do now? The point is it's your investment no-one elses, don't listen to these people because they have no idea about the market it's your choice and yours alone. These sorts of threads are designed to trip newbies up, because others don't want mass adoption of others alts at lower prices, they want to raise the prices of their BTC and they know that other alts can dominate BTC entirely. So my advice is don't listen to anyone and make your OWN decisions.
It's always good for newbie to read a few opinion of others and decide on their own (like what I am doing now). If the newbie just follow blinding then its his problem...