Well... No. It's complicated, but there are several ways in which Russia's invasion of Ukraine have both directly and indirectly increased gas prices. Some of them most definitely are part of 'simply because they can', but the invasion has given people more handles to do that as well.
If there is a significant drop in available supply, prices go up. There are not that many suppliers in the world who can do this all on their own without causing themselves very significant financial harm.
This is why OPEC, when it has it's act together enough for everyone to go along with it, has been such a thing, and holds so much power. If almost every supplier is part of OPEC, and OPEC decides to decrease supply, well, prices go up, and none of the suppliers take a hit.
In a very similar manner, if people think or expect that supply will decrease, you get a very similar effect, despite there being just as much supply as there was 5 minutes before the news or rumor went out.
And, of course, it is perfectly possible for suppliers to sell their product outside of the global commodity markets. It's rare, because it's almost always going to be selling it for less than the current market prices, but today we have some good examples of this.
Russia was a huge supplier of various petroleum products, and even though the oil you use to make gas and natural gas are rather different products, to a limited extent they are just barely interchangeable enough on the usage end that a significant shortfall in natural gas can be partially made up by increasing usage of gas, at least in some places.
(See Europe going through an exceptionally cold winter while not having enough of a natural gas supply to be confident in even normal usage.)
At the moment, you have Russia almost entirely excluded from the global commodity markets. Russia choosing to sell outside of those markets at a significant discount, to evade sanctions. Which gives other oil producers just a hair more leverage in continued price control.
All of this is the backdrop for the international companies that do most of the oil prospecting, drilling, etc, who have all decided to almost entirely stop bothering to continue investments in opening up new oil deposits. These most definitely impact pricing as well, though on a longer time scale.
It's a complex mess, with quite a lot of gambling, and actors who have a vested interest in screwing with the system, and entities with enough control to not only gamble, but to tilt the result to avoid losing those gambles if they really need to.
And given that everyone involved wants to make as much money as possible, only the fact that it is a global market keeps prices even remotely sane. Any excuse to hike prices will be taken.