Battery charging

I was looking through the manual for my Outlander and noticed it said not to charge the battery while it is connected to ATV. Knowing what I know about 12 volt I would have to call bull on this. Am I missing something? Sure if I was trying to desulfate the plates and pushing around 16 volts I would disconnect the battery but anything under 14.5 volts shouldn’t hurt a thing as the alternator should be putting out this much.