This ban is anti-democratic and against the public interest. Limit it to senior officers who directly brief elected officials on a regular basis and ones who are employed in PR roles.
Government rules ban any public sector worker above a certain wage or who briefs the public from publicly engaging in "political" discussion. This was to prevent councils having unofficial politicans on the payroll.
It applies to any matter where two politicians have different opinions, not just party politics. Say the local council wants to sell the local park for housing and turn your quiet side road into a dual carriageway. Some local councillors oppose it. That's political, and by Law if your earn above (I think) £28,000, you cannot sign a petition, write to the paper or speak at a local consultation meeting. If you do you can be sacked.
No public sector worker – council or Civil Service – above a certain grade – can legally post ideas on this site. They are bound to be opposed by someone somewhere.
It means a huge number of knowledeable, bright and/or experienced and articulate people are banned from contributing to local and national government of their own country.
Saying exemptions can be granted is not the solution. Sometimes people do not see eye-to-eye with the boss and want confidentiallity. Any insider posting information about council or Whitehall inefficiency here is legally banned, even if they keep it to general details.