I agree that Danny does really well against aggressive fighters, but I think it's mainly guys who are also fairly orthodox in their approach. For example, a guy like Lucas Matthysse, who is aggressive but not terribly unpredictable. Porter is sloppy, dirty, big for the division, very strong, and very athletic. He gave Keith Thurman hell in there, and I think Thurman is more equipped to deal with a guy like Porter than Garcia.
I think Danny would be a bit overwhelmed by Porter's mauling, and I don't think Garcia has the cardio or style to control Porter for 12 rounds like Brook did. Danny has decent but not great cardio, and Porter is an exhausting guy to fight. I could see them both having good moments up until like round 7 or 8, but I just can't envision Danny winning late rounds against Porter.
Danny has good pop, but Porter's chin is granite. He's taken the best shots Thurman and Brook have to offer, and he's never really been badly hurt. I'd put Garcia in the same category as them as far as punching power.
I just see it as a bad matchup. I don't think Porter is necessarily better than Garcia, in some ways he's definitely not. It's just one of those fights where one guy seems to have a bad style for the other.