Sol, I don't get it either. I mean, if you are totally anti government (hardcore libertarian or whatever), then you just don't want to pay people with your tax money to work for the government. So whatever.
But beyond that, I suspect it's just reflexive, mostly ignorant, ideas about what kinds of work federal employees do, how much schooling and how many degrees are required for those jobs, and strange ideas about monster pay checks, free healthcare, giant pensions, and other imaginary bennies. Partly might be due to the fact that many people only notice/encounter low-level admin or paper pushing feds, and studies do show that their overall benefits package tends to be a bit above the private sector. But the majority of feds are high-skill, multi-degree people in STEM fields or health care, plus a lot of actuarial types. They are paid well, IMO, and I'm appreciative that we will have a decent pension for my husband's work. But it's not going to be ginormous or anything.
It's kind of like the incredibly common misconception that Members of Congress get THEIR SALARY AND FREE HEALTH CARE FOR LIFE FOREVER ONCE THEY ARE ELECTED THOSE BASTARDS! People believe what makes them feel good, even if it's amazingly inaccurate.
State and city pensions are another thing. Extremely variable, and some are definitely totally out of control.