There is no one size fits all when it comes to just about any human activity. As a believer in freedom and self determination, it would be hypocritical of me not to be also for free speech and I am all for it.
Now for this particular issue. People are and should be free to protest anywhere at any time and for any reason or cause. I recall a few years back in New York there were "zones" created for protests, of course well away from the main attraction which was one of the political parties' convention. It was a gross violation of free speech. Then again nothing is absolute, and it is a very easy transition from expressing one's position to harassment or becoming a public nuisance or safety hazard. Anticipating or predicting that is impossible and taking precautions only results in infringements on the rights of people. So I say let people protest in front of the clinic or anywhere they can legally and have the protest monitored by law enforcement. If and when the protest or some protesters over step the line let the cops do their jobs.