They allowed the broadcast, but none of them showed it live. Russian TV showed recorded bits of it on the 21st July according to the German Wiki page.

Couple of people from the DDR are among these german language interviewees saying that it was too big a thing at that time for the authorities to deny it and that people had TV equipment to receive the Western broadcast anyways. In this case better to admit it and show a recording, rather than claim it didn't happen, especially as the Soviets had had so many space firsts already.

Scientific American posted an interview with Sergei Khrushchev some years ago:

Where were you when Neil Armstrong and Buzz Aldrin landed on the moon? I remember the moon landing very well. I was 34. I was on vacation with my friends, most of whom worked at the Chelomei design bureau. There was also an officer from the KGB. We were in Ukraine, in Chernobyl. It was exactly the place where they later built the [infamous] nuclear power station. The KGB officer had just returned from Africa, and he had brought a small telescope. So we looked through the telescope, but we didn’t see any moon landing! So it was still questionable to us! [laughs]

How widely was the news of the moon landing disseminated in the Soviet Union in advance of the event? Of course, you cannot have people land on the moon and just say nothing. It was published in all the newspapers. But if you remember [back then] when Americans spoke of the first man in space, they were always talking of "the first American in space" [not Yuri Gagarin]. The same feeling was prevalent in Russia. There were small articles when Apollo 11 was launched. Actually, there was a small article on the first page of Pravda and then three columns on page five. I looked it up again.

What was the mood in the Soviet space program when astronauts from Apollo 11 landed on the moon? It was very similar to feeling among Americans when Gagarin went into orbit. Some of them tried to ignore it, some of them were insulted. But I don't think it had a strong popular effect. First of all, the Soviet propaganda did not play it up or give too much information. I remember I watched a documentary on this. It was not secret, but it was not shown to the public. The Russian people had many problems in day-to-day life, they were not too concerned about the first man on the moon.