Does that mean submarines never used active sonar and radar?

Not necessarily. It meant that they used it sparingly and cautiously. You would always have been listening on sonar, but it has always been very rare to use the active mode to send out search pulses. That may be even more true today since passive sonar has improved so much. For reference, recall the scene in “The Hunt for Red October” where the captain asks his second in command to send out a second “single ping”. The second in command looks at the captain in total disbelief, as if he had lost his mind. The movie is fiction, but that part of it, and much more, is quite accurate.

In WW2, active radar was used by submarines more often than active sonar. Aircraft were a main concern. An air search radar was available early in the war. It didn’t provide much information beyond the presence of an aircraft. It was also on a frequency that the Japanese could easily detect. Since the information was still important, captains would use the air search radar very sparingly. When a new surface search radar became available, and it included some aircraft detection, it was used more often. However, it was still used sparingly and often wasn’t trusted to locate aircraft in the area. (Refer to section on electronics for more information.)

Late in the war, a radar was added to the search periscope to provide accurate range information. This would be a narrow beam and a single pulse making it hard to determine the location of the source. More importantly, it was a different frequency, making it that much less likely that the enemy was listening for it.