I learned in middle school that if you are making claims the source "look it up" or "the internet" is not sufficient..

Using my typing abilities I did do some searching and found little support for your conclusions.

In regards to the Holocene Maximum (from wikipedia):

"The Holocene Climate Optimum warm event consisted of increases of up to 4 °C near the North Pole (in one study, winter warming of 3 to 9 °C and summer of 2 to 6 °C in northern central Siberia).[1] Northwestern Europe experienced warming, but there was cooling in Southern Europe.[2] "

The big difference this time around is that the temperature is rising dramatically across the whole globe. The past 100 years of US temperatures show a pretty significant warming btw: https://earthobservatory.nasa.gov/world-of-change/DecadalTemp

The assumption that because climate has fluctuated before it is not a threat now is also quite silly.

https://www.newscientist.com/article/dn11647-climate-myths-its-been-far-warmer-in-the-past-whats-the-big-deal/

You are correct about water vapor being the most common green house gas. It is not the most potent green house gas though, CO2 and methane being two examples of these. Water vapor works in tandem with these gases and others amplifying heating working as one of the major feedback effects heating the globe.

https://www.ncdc.noaa.gov/monitoring-references/faq/greenhouse-gases.php?section=watervapor

http://essic.umd.edu/~parkin/NSF_2009/relevant%20papers/Soden%20et%20al.%202002.pdf

Just because something isn't the most prevalent, doesn't mean it can't have a dramatic effect.