I don’t see what’s hard to see here. Washington DC cannot vote for President precisely for this reason.
And your observation about most federal employees being conservative ... I don’t think so. There are ample stats to look at in regards to the breakdown of ‘identified as democratic’ and ‘identified as conservative’, there is even a disproportionate amount of minority and women in the Federal Workforce as well.
The fact is, Federal workers become a ready made constituency for people willing to give them lots of money, lots of union representation, and lots of benefits.
Take away their vote and take away their campaign contributions.
It can easily be done, all new hires and re-hires lose these mechanisms for furthering their agenda through graft, kick backs, nepotism, blackmail, bribary and the opposite end, threats, intimidation and retributions.
“I don’t see what’s hard to see here. Washington DC cannot vote for President precisely for this reason.”
Washington DC has 3 electoral votes for President.