There are meetings and there are meetings.
Class I Time Wasters - all hands status reports. The PM doesn't know the status and needs to have everyone in the same room to feel important. You mention these, and you have a sensible approach -- you've posted the status elsewhere.
Class II Time Wasters - watching a manager think. The PM has to present something to higher up the food-chain and you have to help them do it. In short, they can't seem to read or write without reading to someone or having someone watch them type. You don't mention these, so I'll assume this just doesn't happen to you.
Planning meetings can be Class II time wasters (watching a manager pull together a plan), or they can be very important. Planning often involves tradeoffs, choices, identification of roadblocks, alternatives and -- well -- group thinking. You may not like it, but your job may depend on your participation. You mention planning; you don't like them.
Are they time-wasters -- because you've posted the plan and it's not negotiable -- or is there some additional decision-making that is happening?
Other meetings may seem wasteful to you (because you already know things about the project, the business case or the technology). But they may be crucial for others to learn those things from you. Or decide things with input from you.
Two of the tenets of the Agile Manifesto include the words "Interaction" and "Collaboration" as being really valuable -- more valuable than the alternatives. And Agile practices often involve meetings instead of tools. Similarly, no value meetings can be compared with high value meetings.
The question about meetings is:
Is it information that's most efficiently communicated in an all-hands situation? A class I time waster is a meeting that everybody didn't have to attend. It could have been done as a series of one-on-ones.
Is it a decision that requires several people? A class II time waster is a meeting in which the decision has already been made and communicated, we're just updating the powerpoint together.
Many meetings -- while tiresome -- may have nuggets of importance. What's important is to spot those moments of good stuff happening (and who got value from the meeting) and provide appropriate feedback how the meeting was of benefit to you.
Simply beefing about meetings falls on deaf ears. Managers love meetings. That's why they're in those positions.
Comparing specific high value meetings and low value meetings, however, hits a manager where it counts. Facts. Value. Improvement.