>So what do I do? Shoot down all of your satellites with a "if I can't have them, nobody will" mindset.
You're saying that, as if the country would just let the satellites stay operational otherwise. They may hold off from using anti-satellite missiles, but that would be out of concern for their own satellites. Which doesn't exist in case of jamming.
Even in the scenario where countries only resort to jamming (since it's relatively cheap and doesn't do permanent damage), you'll end up with very limited number of satellites, which may result in significantly reduced coverage and resolution.
largely a speculation, because countries tend to be rather secretive regarding this matter. The point being, we can't evaluate things accurately enough, because we simply don't have the information to do it.
>is easier to defend
Countries can be pressured, local political support can disappear, maintaining presence can get very costly very quickly and it costs political credit. Many countries in SEA would rather prefer to be on the sidelines of potential conflict with China. Having CVs gives you options and more flexibility (like letting the countries be "neutral, but not really", which wouldn't work that well if you actually had to launch all strikes from their soil) which has its value.
I'm not even claiming that CVs are definitely very useful. I'm just saying that it's hard to judge, and that your theories are largely based on conjecture and not too reliable.