Temurah

The Gemorah (Temurah 3a-b) says that temurah is an exception to the normal rule that there is no punishment of lashes for a lav that is violated without an action.  Rav Yochanan doesn’t include it on the list for it is considered to have an action and that is the speech.  Seemingly this would fit the opinion of Rav Yochanon in Babba Metzia (92a) that one who muzzles an animal by yelling at it is considered to have violated the lav of חסימה through an action.  The Rambam (Temurah 1:1) rules like Rav Yochanon regarding muzzling the animal but not regarding temurah, why?

The Mishna in Temurah (14a) says that if the animal is owned by partners or collective ownership temurah can’t be done to the animal.  The Rambam says that even though they can’t create a temurah, the lav applies to them if they attempt to make a temurah.  We see that the Rambam holds the punishment isn’t for the chalos of the temurah, it for the act of the מעשה תמורה.  The Rambam sees in this halacha that the punishment isn’t because your speech caused a chalos, it’s because of the attempt to make the temurah.  Based upon this, we understand why the Rambam rejects Rav Yochanon in regard to temurah but accepts him in regard to muzzling the animal.  When it comes to muzzling the animal, the yelling at the animal is the cause of the חסימה and makes the person eligible to lashes.  However, regarding temurah, the speech doesn’t cause any action, it is the possuk that causes the chalos.  

The Maggid Mishna (Secherut 13:2) suggests that speech is considered an action only when the normal way of violating the lav is through an action.  Hence, when it comes to חסימה, since it is normally violated with a regular action, we consider speech an action as well.  However, תמורה which can only be violated with speech, then speech isn't defined as an action.  This idea needs an explanation, what kind of סברא is this that if the lav can be violated with an action then speech is defined as an action?