Earlier quoted context omitted.
It's a common mistake. Just this weekend I followed a recipe from a well known cooking website for beef stroganoff that said to brown the beef in batches together with batches of onion. That's not a good idea, the onion will release liquid which prevents the beef from browning and once that cooks off the heat required to brown the meat will burn the onion. So I cooked the beef and onion separately instead. The onion…
I cook pasta at a rolling boil not because it cooks faster but the agitation of the boiling makes it less likely to form sticky clumps.
I’ve always used the rolling boil for stirring when making macaroni or other noodles. Maybe a minute of agitation in the beginning to get it going but it lets me set and forget. Maybe add a teaspoon or two of an oil to knock any bubbles out to avoid spill over / foam.