Earlier quoted context omitted.
If you'd done the same thing with a bust of your mother 10 years ago, they'd have covered it up as well. Try the same thing (with Snowden, or your mother) in France or China, and see what happens. Just because they parks department is doing their job doesn't mean democracy is ebbing.
Do you have examples of precedent where this occurred in the U.S.? If not, you're simply speculating based on your own opinion/mood/blood sugar level. Graffiti is rarely covered up so quickly unless it is found to be particularly offensive. My personal belief is that this statue was deemed to be politically offensive and inciting as well as likely to draw media exposure and so was quickly removed from view even thoug…
So the right thing to do now is to put up a politically innocuous statue and see how long it lasts, or to find cases that are closer to this situation than graffiti, which is both commonplace and relatively less obtrusive, and less likely to be taken for an "official" statement of anything.
I used to live beside a park where a local artist erected an extremely strange Transformer-like statue in a central location that took several weeks to be removed, but it wasn't in the US and it was in the poorer area of a small town, so there are too many differences to draw any useful conclusions from it.