I think the point is that people are being killed and attacked all the time in the UK and the police do nothing because basically they lack the resources as a result of funding cuts, which were voted on by the same politicians who are now complaining that the police aren't doing enough
No they are not, you are exaggerating! we are not all being murdered and attacked!
Police numbers are similar to the early 00's now and cannot patrol every street 24/7.
All serious attacks and murders are investigated and arrests made in many cases, the recent train stabbing led to an arrest/charged very quickly.
The point here is that the Police were in attendance and whilst i have no problem with people chanting whatever they like at MPs (subject to the law) the close physical contact should not be tolerated, acid or a knife could have been used on Jones or Soubry.
By doing nothing, the protestors (from either side) will be emboldened and go farther next time.