Constructionism is the idea that things are social constructs, (Yes, even the thing you're currently thinking of when you read that sentence.) Constructionism tends to piss a lot of people off on the internet, because they hear social construct and think "Not Real."
But of course they are real, we each construct our own understanding of the world through our education and life experiences, and narratives, and that determines the things we think are real and important. While no one philosophy is the right tool for every situation, constructionism is useful for examining the underlying assumptions and ideologies, and narratives around a topic, that people doing more empirical and positivist research on the topic might not consider.
I think it pisses people off because it is a good tool for challenging worldviews, and it is useful for considering and critiquing why people believe the things they believe about the world. Constructionism serves to critique the assumption that research, education, communication, or any action done by humans can be value neutral and free of agendas. Social constructs are absolutely real because of the all encompassing effect they have on people's lives, but if you are not aware of them it makes it harder to consider alternatives.
