Actually, as you can tell from the way Sammie bolded your quote, it's obvious they were responding to your anxiety about wanting to get everything done right away. In that context, the advice was both accurate and helpful.
Obviously, when you are renting, you are on the owner's timetable and are at the mercy of their schedule and priorities. They may not be able to respond quickly to everything a renter wants, or they may simply have more important things to do.
Sammie's advice is helpful because when we answer questions on a public forum, we're really answering to the public...not just to the OP.
You may be perfectly comfortable with renting, and may have had numerous positive experiences in the past. But not everyone reading the thread is in that boat and a caution like Sammie's is often helpful to folks who don't know much about renting. Being subject to someone else's timetables and responsiveness IS one of the legitimate drawbacks of renting a reservation.