When I came to the US from Europe, I had no credit history and that made it difficult to get any type of credit card, or loan, or anything. I thought it was a catch 22 since I couldn't build credit because I didn't have credit, but there is this thing called "Secured Credit Card", where the bank lends you your own money (that you deposit) to see if you can repay yourself. Had to do that for about a year, and I also managed to get a Macy's card with a $100 credit limit (yes, one hundred) that forced me to shop there to "build credit".
After that the climbing of the ladder started with credit limits increasing slowly, etc... up to the point that I was able to get a loan for a house.
There's a bit of strategic planning to building credit worthiness, and that requires you getting into some "managed debt". I think that was the spirit of the comment you are asking about.