Didn't read the article, but I'll mention, as someone with formal training in building clearing, if you are doing one and you see surveillance equipment you destroy or disable it as soon as possible because, as Charby pointed out, it could be being used to observe your movements and direct opposition to tactically advantageous positions.
So, if a tactical entry is warranted the destruction of the cameras is pretty much SOP. It also shows more professionalism then PD's normally use in these entries. So kudos to them.