Probably not "doctored" such as adding more people but simply cropped to give a desired look.
Shot from a low angle with a very long telephoto lens. That technique compresses the depth of field and "stacks up" crowds. You can tell that this is what's going on from close examination of the first few rows. They look about 10 feet apart. But once you get past them, only a "sea of signs" is visible. 1,000 people perhaps? You can almost count the signs - perhaps much fewer are there. I'd presume that each one has a sign.
If the crowd was larger, a higher angle would have been used for the shot.
Quick look, I think it is doctored. Look at the pattern of those black signs to the right. The left will do anything. They are unethical creeps.
Looks like they filled in all the spaces w/ their favorite color....yellow.
Exactly. It's framed and cropped in a way that implies—promotes the perception of—a densely packed crowd of people that seems to stretch to infinity. If you really look closely, you can start to see that there is no massive number of people there.
They bank on people not looking closely. They've been doing this same thing with "crowds" of leftists forever, whether it's a couple dozen worn out old feminists or a few hundred anti-war losers like this.
MM