Emphatically no, cyclists should mind their own business. There's more than enough aggression and ill feeling on the the roads already without self appointed little Hitlers adding substantially to it.
The correct channel for those feeling more action is necessary is to lobby for more enforcement by the correct authorities, not to presume the enforcement is for them to carry out at risk of creating breaches of the peace.
Cyclists no shouldn't as this should be left to police to watch for and catch any perpetrators in the act themselves , always wanting Joe public to do their jobs at times
this when they get paid well for such, and so its their job to catch anyone
using a mobile at the wheel, but then again if a family member of a police officer
is seen using a mobile phone at the wheel, then seems that they don't get into troubles
for such this I know , in which is way wrong .
Im against anyone using a mobile phone at the wheel of any moving vehicle .