That would be correct in the case of manslaughter or aggravated battery. But I think they could argue that the “merger” doesn’t apply to lesser charges which contain some new element, as in the case of child abuse. For example, if Florida had hate crime laws to address racially motivated attacks, I don’t believe they should be able to add this on since it would add an element (racism) not included in the 2nd degree murder.
And I totally agree with you. That’s why this question of 3rd degree murder/child abuse is so contentious. It’s adding that new element you’re talking about. The example I read is larceny vs. robbery. Larceny is the illegal taking of property and roberry is using force to commit the act of larceny. So a jury instruction could say, “Well, if you don’t find they used force, you can still find they took illegally.”