In my view, a stereotype can be fairly innocuous or it can be very harmful depending on circumstance and history. When it comes to stereotypes held by whites towards blacks, those stereotypes are particularly harmful because every stereotype that exists about black people, in America, has ultimately been a justification for conquest and plunder.
Some of these stereotypes-as-cause-for-plunder are pretty easy to spot. You say that black folks are lazy and sexually lascivious and that is justification for slavery and harsh Jim Crow laws and police brutality. While the connection between claims of black indolence and hyper sexuality and the supposed need for physical control of the black body are rather clear to discern, the more minor stereotypes about black people ultimately have an ugly history and implications as well.
The stereotype about Watermelons was and is used to show that black people are infantile and are undeserving of political power even within the confines of their own communities. The Black people as loud troupe was frequently cited as yet more proof that black people are wholly unsuited for participation in republican governance. Even something as seemingly positive as the "strong black woman" stereotype (along with the sassy black woman stereotype), is really an invitation to inflict violence on the black, female body in a way that most would never dream of inflicting on a white, female body.
In a perfect world, we would never indulge ourselves in stereotypes of any kind but since we do, it is wise to rank stereotypes based on their context and their intent. Within the context of white people in America, virtually every stereotype about black folks was and is, more or less, a casus belli against the black body.