You pose some excellent questions, some of which you can find answers to in previous postings on this thread.
To elaborate a bit further, you need to realize that Hebrew is a beautiful language (I speak from experience with fluency in 7 languages) in which words have multiple meanings, borrowed meanings and convergent meanings. Some single words in Hebrew require 8 or 9 words in English to be satisfactorally translated.
The Hebrew AUDUM (I transliterate on purpose so you don't automatically think "Adam", the name of an individual, when you see that word) has three different meanings throughout the Bible and even in modern Hebrew. The word can be used to mean (1) human, humanity or humankind, as a species, (2) man, as opposed to female, and (3) Adam, the name of any individual by the name. In Genesis the word is employed in all three ways, depending on the context. It is actually easy to ascertain which meaning is intended from the context.
In verses 26 and 27 of chapter one, quoted above, the context makes it absolutely clear that AUDUM there refers to "human". There can be no reasonable doubt about it.
So why are some popular English translations wrong? For a combination of reasons. Ignorance, preconceived notions, mischief making, sloppiness, and agendas to be acted upon.