Is it a violation of federal law to use force with the intent to injure, intimidate, and interfere with anyone because that person is a provider of reproductive health care? Yes or No..
Sure.
Is shoving someone using force? Yes or No....
Yes, but it is not illegal if one is defending oneself or others during one's lawful protest or demonstration, even if that protest/demonstration occurs at an abortion clinic, and apparently, the scenario is not as simple as the guy walked up to the escort for no reason and shoved him. Apparently, the guy was in the process of harassing a 12 year old boy, and this was the 12 year old boy's father. Obviously, the facts will be what they are ultimately proved to be, but in 2 seconds I found out that the story was more complicated than was presented in the OP.
Why does the Freedom of Access to Clinic Entrances Act exist?
Ostensibly, the avowed purpose was to stop anti-abortion people from blocking the entrances of abortion clinics, which is a valid purpose, in my view. However, on the other side of the coin, it also criminalizes protests and other behaviors that are purely verbal, by calling it "harassment" when that same kind of protest would be considered free speech in any other context.
However, that's another issue, as what we are dealing with here is "shoving," which is decidedly not free speech. The issue becomes whether the shoving was justified or excused in any way under the law, which remains to be seen.
Some of the outrage about the arrest relates to how it went down. I mean, you have city police and the district attorney decline to prosecute. Then, you have the FBI send the guy a letter, and the guy responds to the FBI looking to discuss the matter, and instead of having the guy come in to the FBI office and discuss it with counsel present, the FBI sends out like 25 guys and busts him with guns drawn in front of his wife and kids. For shoving. It's a second degree misdemeanor - MAYBE -- if it's proven and serious -- and in this case we know that the state authorities were not inclined to prosecute. So, it does seem, at first blush here, that this is another case of the FBI really going out of its way to do something in a heavy-handed and over-the-top fashion. What jumps out at me is that they are sending a strong message - you are really risking it big-time if you go to an abortion clinic to protest - and if you get drawn into a shoving match, it's you that's going to be arrested.
And, the punishment seems excessive - 11 years in prison exposure for shoving? Err.... it's this kind of thing that does get people concerned about our criminal justice system. Any self-respecting liberal would be looking askance at this sort of thing. All it takes for this kind of power to be leveled against a person or group you sympathize with is a change in leadership.