they can, and they did, for example, for the browser ballot in windows.

This was not a law, and so a very different situation. This was a court ordered remedy for a conviction.

Courts generally have the power to fashion appropriate remedies, and yes, sometimes they involve compelling speech or other things.

(Some of these remedies have been struck down depending on what they have been forced to say or not say).

Warning stickers on cigarettes are mandated by law.

That is a labeling requirement for health, not compelled commercial speech (which again, is about commerce :P). It does not require them to state anything about themselves, just about the risks of the ingredients in cigarettes.

You need to understand these are all very different things in the eyes of the law

Also note the

A. current warning labels were litigated, and tobacco won at the district court level: http://www.news-record.com/content/2012/03/01/article/judge_...

This order was reversed by a divided panel on appeal: http://www.journalnow.com/business/business_news/local/artic...

The supreme court declined to hear the case (which means nothing :P)

B. Requiring phillip morris, et al to make ads stating they deceived the public was not okay. http://www.claimsjournal.com/news/national/2015/05/22/263534...

etc

These are all very complex constitutional free speech issues, and trying to simplify them like you have with a throwaway line doesn't work well in practice.