The tools_condition is a general purpose routing function. It checks the state to determine if there is a tool-call and route to the appropriate tool node. The problem is where should it go when there is no tool-call? If it defaults to the END as you mentioned, then it would be less flexible. Because, with no tool call, the graph may want to do any number of things and not just go to the END node. So in order for it to play safe, tool_condition creates a conditional edge to every other node except the one it is currently on. Hence, you get the extra conditional edge to the report_checker node

However, when you create a routing map as you have done, it removes the ambiguity as it knows where to route to in case of no tool call.

I hope this answer your question