Why does my macbook pro 15" mid 2010 6.2 restart on its own

Why does my macbook pro 15" mid 2010 6.2 restart on its own mostly on Facebook almost immediately after posting criticism toward the Trump administration? Using high sierra 10.13.6 and Safari. Also,why after changing out my apple Time capsule being used a router with a new one, the problem disappeared for around 10 days. Now i get occasional restarts usually when i'm on Facebook and i'm posting about our Governments new policies agendas.


The restarts would sometimes be 15 to 20 per day.. Now its 2 or three.. I took my computer to an apple store and they checked it out and found no hardware issues.. I erased my drive using a military erase which took 12 hours and reinstalled a fresh operating system. It still continued,but started out with much less restarts,gradually building to 15 to 20 per day.. The Router replacement took place because my Apple time capsule had failed to back up my hard drive but i was using it as a router. So i used the new one my cable service provided and discovered the difference.. I bought a third router after the second router started having the restarts again after a period of 2 weeks. Third router made the difference and there were no restarts,however after a month i started having 2 to 3 per day. I am considering buying a 4th router but i think apples Safari has an open back door because when i use Firefox i rarely get a Restart. It sounds crazy right! But i can draw no other conclusion based on the observations i have made regarding Safari Facebook and my freedom to voice my opinions on our present state of politics.