Stats and polling is a science. Granted practitioners do not always do the prep work, or sample validation they need to do to validate the samples.

However, your points 1-4 are examples of poor quality work, and are not problems with polling science per se.

1. True that not every population will follow a normal distribution on every question. Usually this work is done up front to qualify and profile the population in order to use it later and tied to larger predictive things like income. This pre-work for the US was generally done long ago and is out of date and needs a serious re-work. Even if the population does not follow a normal distribution, there are still probability tests with error margins that can use any of these other type distributions.

2. There is supposed to be an 'other category' for those who don't agree with the questions posed. Really good samples might also phrase the questions in different ways to see if that correlates to changes in the distribution to see if there is introduced bias. They would also do a test of their samples on a 'complete' sub-population to validate the larger sample.

3. A poll is a snapshot in time and does not indicate past or future behavior. Mis-understanding of what a poll is. Also, unless the poll is somehow anonymous, there is also peer pressure bias introduced as people may say what they think is politically correct.

4. You missed a major population bias which is very important now. 'Calling' people is no longer a random sample as people who have land phones, answer them to unknowns, and are willing to talk to pollsters are not representative of the population as it may have been in the 50s and 60s. Other population studies have shown this 'called' population to be older, whiter, more rural and more conservative. For political purposes, more 'republican'.

As I said, the science of polling is good, even though some of the practices of the firms done today are not. Work on pointing out the flaws and bias in the practice, not in the science itself unless you have worked out some new quantum fractal alternative reality probability theory deserving of the Nobel prize. Otherwise, the progressive wing begins to resemble the know-nothings of the ignorant and delusional right wing.