I oppose abortion but oppose such protections. Why? Religious conviction should not be a cheap thing and such laws cheapen the conviction. If a person truly opposed such practices then the best solution is to find another line of work or an employer more accommodating rather than forcing the employer (by point of gun) to go against their convictions.
Here is a case in point why we do not want to let the government protect employees not doing their jobs. Sooner or later such protections will be applied to employees who object to t-shirts:
The government has no business in protecting employees who out of conviction refuse to do their job no matter if the conviction to not do the job arises out of religious conviction or moonbattery. In the case Power Line notes having the government step in would team the force of government up with the miscreant employee to suppress customer's freedom of speech. Now, if the employee and the employer said no one may express the sentiment sharp cheddar cheese is the best cheese in their store that is fine (after all, no one has the right to use another's property to advance causes opposed by the owner), but the government may not add force one way or the other to that prohibition (remember government forced speech is not any freer than government suppressed speech).