Risk as a thing is never zero. The question is how to mitigate the risk of complete loss. Also couples nicely with your other question around what is worth doing, even if failure in possible or likely.

There is a fine line.

For instance "don't get into huge debt to bet on a very risky investment" is a sound advice.

Once you have tried risky investments with little to lose and are fairly familiar with risk mitigation strategies, risk profit calculations and so on, it may lose it's appeal, but it's a good starter.

I assume most advice you were given could be used in a similar manner.