Uh, the advice here is not generally to rent.
The advice here is to run the numbers and figure out what trade offs are most worthwhile in terms of preferences and costs, like any other financial/lifestyle decision.
Most people buy or rent primarily for lifestyle reasons. Very, very few people are comfortable with either/or. Almost no one makes the decision purely financially.
The people who are willing to rent long term might be more flexible in their decisions, but the people who are determined to own, are just that, determined to own, and they're willing to trade off whatever they need to in order to do so.
As for whether you already own a home or not, it has no impact, other than to factor in the transaction costs, which is a very simple addition to the math.
So no, the question is not meaningfully different for those who already own houses.
Look at your options honestly, assess what's best for you, and do that.