It does interfere with their job, as it makes editing the interview into a hatchet job piece of agitprop much more difficult.
In many, but not all, instances there were multiple media types filming the same interview, and others doing the same thing sometimes would be within the frames of their shoot. No one ever complained.
In the instance cited here, the filmer was filming a friend being interviewed and should be allowed to.
Experienced media people have no problem with someone recording their interviews, this one seems a bit green, wet behind the ears.
well said