The comments you referenced sounded more like disclosures than countertransference although as I don't have the full description of it, it's always hard to say.
Disclosures can be very beneficial. In appropriate amounts it can help clients feel they are not alone with a problem. It's normalizing. Inappropriate disclosures occur when a therapist vents about their own problem in a way that the client feels the weight of it and it interferes with their own work.
Countertransference can interfere with therapy when a therapist is unaware of their own issues and how they are distorting how he or she is experiencing the client. For example, if a therapist was unaware of their own impatience and a client picked up on it, the therapist might misinterpret the client's reaction as missplaced.
It's not unusual for a therapist to have countertransference. It's his or her awareness about it that's key.
It's a huge subject so I'm only covering a small part of it. Hope it clarifies some of it.
Shrinklady