Bedrockgames
I post in the voice of Christopher Walken
I think your mention of tables is a key element here. I feel like that is what helps maintain some kind of simulation that doesn't just devolve into the GM deciding things. So if you have a weather table, and the results on the table have taken into account the kinds of weather possible for the time of year and location, and then you roll on the table, that to me seems far more like simulation than simply deciding on one of those results.
When I think of simulation, I think of the outcome of the simulation being beyond control. That's usually the point of a simulation... to see how things turn out. Simply deciding the outcome seems contrary to the idea of simulation, in that sense.
This is why I'm struggling to accept a GM deciding the outcome as an example of simulation.
I think that this then leads us to deciding the method of determination. How we decide what's on the tables and similar concerns.
It really depends on what a person means by simulation. I don't think there is a single definition. It is a term I generally avoid, though in these discussions I often do see some of the things I like to do filed under simulation and so I defend the position. But like I said before most campaigns are a mixture of different styles and approaches, not just focused on one thing. What I think we are really talking about here for most people is a sense of believability and realism and a sense that the world outside you exists. That can be achieved by random tables (personally I love random tables for that reason). But I have been in campaigns where it was handled by fiat and or prepping things in advance and I am fine with that too as long as the feel remains.
In terms of simply deciding, I think if the GM is genuinely trying to logically work out what might happen, then it is fine. Obviously a lightning strike is hard to figure out in your mind, so maybe a dice roll is called for. But even if their method is just picking something that seems realistic, I am fine with it, as long as it doesn't feel overly arbitrary or convenient (or happens to push us a long a path they had in mind in advance). For instance if a GM just decides that Old Jeb's house burned down from a lightning strike and we meet up with him weeks later and learn about it, that is sufficiently plausible and external that it fits what the GM is trying to do in my mind
Personally I don't get too hung up on methods or procedures. I see them as tools groups can use or not, as they wish.