Some open source code is like food poisoning by getting food off the road from a random person. It will make you puke your brains out is a good analogy to explain how insecure the majority of the code written by individuals is and how you can lose everything. Other open source code from companies is more along the lines of getting food from a food truck, which is a company and the majority of companies try to deliver a safe product and not one that is the equivalent of food poisioning.
Macintosh Malware is on the rise. In 2017 Macintosh malware rose 270 percent in one year. If anyone tries to tell you Macintosh is bullet proof, they are wrong.