It certainly sounds like he's talking about a condo association ("unit"), not an HOA, which tend to care about different concerns. Rules like this make it hard for an owner to
not be aware of negative impacts that their property is inflicting on their co-owners. You know--the other people involved in the
con-dominium. Words are fun and educational, aren't they?
So, yes, there is a positive side. Most people have lived in places with absentee landlords. Many people don't want a preponderance of absentee landlord properties in a place where there is such direct impact from doing so; the thinking goes that if you rent out a house across the street from me, they might be annoying, but if you rent out a condo unit above mine, your tenants might flood my apartment because they didn't tell you the toilet had problems. Important difference.
If you don't like that, don't buy into a condo association that does it. It is extremely rare for a rental-limit rule to be put in place these days, so in practice you should know going in whether those rules are in place. If by some chance you live in the one in a thousand that does try to put those rules in place today, sell and move on.