Home runs don't bother me. It's what damage is done with those home runs that matters.
Porcello has allowed 148 home runs in his career. 86 have been solo, 44 have been with 1 on, 17 with 2 on and 1 grand slam. That ratio really hasn't changed with Boston. For Boston, he's allowed 37 total, 22 solo, 13 2 run and 2 3 run. Solo homers don't mean much and 2 run homers normally don't kill you. Of course, you can't give up 3 or 4 of them in a game.
Put another way, a solo homer is 4 total bases and 1 run. 4 singles is also 4 total bases, but would normally score 2 runs and there's still 2 men on base.