You don't need to boycott PP, just tell people to use Bitcoin or Steem Dollar.
It's always amusing when someone says "sure I'll join the boycott because the competing options are better anyway". That's not boycotting. A boycott means stopping the use of PayPal (in this case) particularly in cases where it otherwise makes sense to use PP for a particular situation. The advice to use crypto-currency is independent from the boycott, regardless of whether the advice is viable or not.
Furthermore, you cannot use crypto-currency to pay an organization that only accepts PayPal. Any method of transfer that might land PP money in the recipients hand ultimately still feeds PayPal.
And by boycotting the other companies, that makes up most of the US economy. I am not sure that would be beneficial. But yes, too much power is concentrated in monopolistic behemoths hands.
That's very patriotic of you.
Boycotts are for people to practice ethical consumption. If one nation happens to be home of many unethical suppliers, it doesn't obviate the harm done by patronizing unethical suppliers.
If you want a positive angle, think of it as rewarding the economies of countries that aren't saturated with unethical suppliers.
Some diversity is needed in the corporate sector. Perhaps some blockchain projects.
Ridding the corporate sector of bad players is a good thing, of course even if diversity is temporarily reduced to make room for ethical players to replace them.
RE: Trade Wars