ditto to this one, exactly what I would try to do with the same order.

OP did not tell us how his manager justified his refusal, BUT because of the way he formulated his question and my personal life experience, I'm very much inclined to believe that the manager simply gave not or bullshit/generic reasons as to why he won't let OP give the talk.

That the most common situation is the manager is a shitty person who realises that if by any minute chance OP's talk somehow hurt the company the implications are dire for the manager while if OP's talk do nothing bad for the company, there's nothing to gain for the manager/company -- therefore the manager chose not to allow OP to give the talk.

Which would prove the manager to be a verry shitty human being, just the kind that would elicit employees asking questions like "how do I manage my manager" on the internet.

Why would the manager be a shitty person if they saw no upside for the company, possible downside, and decided against that action? If we were talking about a decision that didn't involve another human being and their desires, I suspect you might find this decision-making logic acceptable.

Perhaps you could explain why if there is no chance for the company to gain anything but a non-zero risk of the company's status, position, brand value, etc. being damaged, why is this a bad decision and the manager a "very shitty human being"?

Because its the man's spare time and since he's not a child I would expect enough trust from the manager that the employee would not do any damage to the company.

There's a non-zero risk to the company if the man gets into a bar fight, there's a non-zero risk to the company if the man crosses the street and gets run over by a truck on his way to work each morning.

First of all, it is almost certainly not his spare time. Nearly all of these events are held on weekdays during normal business hours. So this guy probably requires permission to not be doing his regular job to go to this. Second, there are usually costs associated with attendance. Many employers pay them and perhaps this company didn't want to. But for the sake or argument, let's assume this is held on a weekend and the guy pays out of his own pocket to attend. He's still there representing the company and the company has every right to choose how they are represented and by whom. It's not like he's attending Comic-Con. He's most definitely representing the company, even as a mere guest - doubly so as an actual speaker. The company can choose to say "no, he's not representing us". Maybe he's a really smart dude but a shitty speaker or someone with no social skills or stage presence.

There's a non-zero risk to the company if the man gets into a bar fight, there's a non-zero risk to the company if the man crosses the street and gets run over by a truck on his way to work each morning.

Yeah, but he's not representing the company in such a scenario. And in rare events, when such unflattering incidents like bar fights do actually make front page news for some reason, people are sometimes fired because of it. You know why? Because of this exact same logic.

> the most common situation is the manager is a shitty person

You don’t know nearly enough about the situation to say this. Most managers are not shitty people.

You are right, I am jumping to conclusions based on what I'm reading between the lines: I presume this is not the first time the manager was shitty to OP since OP asked it in general terms how should he manage his manager, and I am also presuming the manager did not give satisfactory explanation for his refusal or offer a reasonable compromise(like "you can go, but you must never mention the company, our clients, our business etc).

I am horrified by the complete lack of empathy and emotional intelligence of such managers.

Won't OP just not hide such "silly" matters from the manager if whatever the matter is OP gets a slap on the wrist?

Is it indicative of good managerial skills that OP felt he should ask about the matter on the internet and not the manager himself?

> * I presume this is not the first time the manager was shitty to OP since OP asked it in general terms how should he manage his manager*

This is not a terrible assumption, but assuming malice on the manager’s part is. Maybe it is a shitty manager. Or maybe the guy asking is a shitty employee who’s constantly screwing up. Maybe it’s something else entirely. There is too little information here to say.

> Is it indicative of good managerial skills that OP felt he should ask about the matter on the internet and not the manager himself?

It’s indicative of a poor relationship. I can’t say whether the issue is with the manager, the individual, or both.