I sometimes think that scientist often mislead us for their own gain.
I'll see your dramatic generalisation and raise you another. Some elements of all sides of this discussion (picking the climate change one first) mislead for their own benefit. Some mislead for piety, some (a great many) for financial reasons, some because they are natural imps who court controversy and brook dissent for nothing other than fun. (IMO) the worst of all are those in the media, on all sides of the media, who sensationalise and misrepresent all facts to try and get a byline or sell a copy. Perhaps the worst actor in the whole play is a general public who are unable to use critical reasoning to cut through the noise at each end of the argument.
In terms of the evolution piece - an average change in stature across much of the population is about improved diet and a few other factors, not 'evolution' per se. Many cultures are also fatter, not an evolutionary change either. But there's no advantage to these changes, there is a change in the average appearance of certain groups of people but that doesn't constitute evolution outside a newspaper headline. Other examples of appearance changes (phylogenic adaptation) are evolution (think Cichla species - mostly they are visual and some slight physical differences rather than gross anatomical changes) but they are distinct populations and counted as different species.
The thing about science that annoys you is what I treasure - the state of knowledge develops and changes as more information becomes available from greater, broader and deeper research. Anomalies are brought to light, challenges to convention are argued and fought over, supporting evidence is weighed. Avoiding the lunatic fringes you can see that most scientists are describing the world according to evidence (not dogma) as it stands at the time. Some things are inarguable - gravity, for example, but the impact and effects of gravity are all being dissected and discussed in ever larger hypotheses.
A few minutes with Google would have brought you an exact definition, but primitive fishes are generally fish that closely resemble something that is known from the fossil record. Arapaima, for example, have changed little over tens or hundreds of millions of years. Cichlid fossils date back up to 50 million years but have changed significantly in response to competitive environments and filling niches, and no surviving cichlid reflects those early fossils. I seem to recall that there are also some classifications of, for example, jaw or skull articulations (distinct jumps in anatomy which aide the survival and breeding chances of a species etc.) that also define primitive from modern fish.
Finally one point of confusion you have which is common - we did not evolve "from" apes in the sense the we were chimpanzees one minute and then suddenly jumped up and started smoking cigarettes and swilling cappuccinos and waxing our backs. We share a common ancestry with primates. Going way back (tens of millions of years) there was a common ancestor, that is who we descended from, not any primate that is living today who also have that species as a common ancestor. There have been other members of the Homo species over the past 3 million years but they have all died out or been absorbed by cross breeding.
DNA studies are starting to show some very revealing traits and patterns regarding the evolution and migration of the human species, though again the data is sometimes open for interpretation; and scientists are still people and get caught up in petty squabbles and outright sledging matches about often very minor points. One could say the get a religious fervour about their science. There is still much to learn and understand and identify about human evolution, though. That is exciting to me, it doesn't call into question the valid knowledge we already have, as long as you are listening to the right voices and avoiding the sensationalised rubbish on television that are developed (mainly) for financial reasons. My rule of thumb is that if the narrator of a documentary talks like Sir David Attenborough then I will take it seriously. If the narrator talks like he's reading the script for America's Worst Police Videos then I presume that is to cover up the lack of actual content.
Cheers,
'Bear
