If it's a single bot that you see you can right-click and target them and "examine" them. I've had a lot of bots port away or log out entirely and this helps getting the details down when you fill out the report. For multiple bots, try to click through them as fast as you can and write their names down somewhere, you are bound to miss some because they spawn directly on top of another but you can report as many as you can.

Also, the reason why it is the way it is is so that people don't abuse the function. If it's a simple right-click report feature how many people will report people they don't like for being bots to try and get them banned? It also makes the GMs job easier because they should have all the information noted down from the person doing the reporting. You are taking note of what exactly the bot is doing right? If you don't write down what the bot is doing there is no way the GMs can really prosecute them for illegal activity.