Adobe's license did not restrict your rights to read the book aloud.

It was referring to the speech synthesizer function of the reader. From an article in The Standard about it:

Why then was the feature disabled on Alice — and why is it ever disabled, for that matter? "Our original intention was to enable Read Aloud for all PDF e-books," Kawell replies. "Unfortunately, the book publishers said that they had already sold the audio rights to many of their titles and didn't want to run afoul of those agreements. So, we created a 'permission' that allowed publishers with such a worry to turn it off."

The fact that the Read Aloud feature was denied to those who downloaded Alice was merely the result of a "data entry error," he said.

It's patently untrue, and yet people keep siezing upon it as a wonderful example of licensing run amok, just as they do with the McDonald's lawsuit as an example of litigation run amok. And yet neither one of these cases is actually the example people think it is.