Question: I am looking for the word/phrase that is used to say that a (potential) erroneous conclusion has been drawn from data without having a correlation to other supporting data points.

For example, if someone has the dataset of the number of red cars sold in the US per month as `Jan: 10, Feb: 10, Mar: 9, Apr: 8, May: 7, etc.` and draws the conclusion of `"Red cars are going out of style"` without correlating this data to total car sales for the same time period, or the number of other color cars sold, etc.

This conclusion might be correct if there was data showing that car sales as a whole have not declined, but this conclusion could be false if car sales as a whole have declined, etc, etc.

Is this called "Sampling Bias" or something else?

Answer: 
I am not clear that you need a technical term here. In your example, someone is jumping to a conclusion based on looking at some of the data only. 

We often do that in real life, as when we judge something or someone by first or brief acquaintance. Sometimes it works; sometimes it doesn't. When we judge the temperature of a bath or the sea by dipping in a toe, or check whether some cooking is ready by tasting a small amount, that usually works. When we judge someone on a first date by something embarrassing, that might be right and it might be wrong. 

Note also that correlation has a very specific meaning in statistics, which you are not following here. Informally, it does have a broad sense of comparison, but within statistics, there is a precise defined meaning.
What you're describing can be summarized as "no control or comparison condition."