The wells in that region produce mostly crude oil and natural gas. Crude oil is easy to store in tanks, put into tanker trucks, and otherwise get off the well site to the market in a variety of ways that you can use from day 1 of drilling the well. Natural gas must either go into a pipeline, be vented into the atmosphere, or be flared (burned) into the atmosphere. Pipelines can take years to catch up to drilling (not really due to regulation as others have pointed out, but rather due to rapid drilling for profitable oil outpacing thousands of miles of pipeline construction to sell much less profitable natural gas, along with lack of enforcement of regulations intended to restrict flaring to a certain time period after drilling a new well). So a lot of gas has to be vented or flared. Venting is considered worse than flaring for the atmosphere (because methane is a worse global warming gas than CO2 as you pointed out), so it all gets flared. Perhaps flaring burns the methane but not the ethane, or at least not all of it, which is why ethane is the problem we are focusing on here?