This equally applies to any investment income wouldn't it? Dividend, loan interest would all be classed as "unearned income" by a certain economic theory I won't name that keeps causing people suffering a century later. Don't do that.
From this, we can conclude that there must be some point after an investment is made where continuing to benefit from it transitions to rent-seeking behavior.
Would rebuilding the apartment every so often straighten you back to profit-seeking?
Rent-seeking is just a meaningless insult if framed like that, it highlights no economically net-negative behaviour.
I guess you could class some rent as predatory as well, allowing others to use your property for a fee is not necessarily predatory (unless you're of "property is theft" kind).