How do medical schools view summer classes?
A couple summer classes (even if they are away from your undergraduate institution) are fine. I could be wrong, but I think ADCOMs are not too fond of applicants taking a lot of prereqs over the summer (e.g. physics 1 and 2 as well as orgo 1 and 2 etc). If you take a bunch of summer classes at "less rigorous" institutions, it can look as though you are trying to avoid taking difficult classes (e.g. taking non calculus based physics when your college only offers calculus based physics). And to be perfectly honest, you will not get the same education out of summer classes. Again, a couple of prereqs are fine, but don't over do it. It can become pretty obvious when people cherry pick classes...
I ended up taking orgo 1 one summer and physics 2 another summer, each along with another class that same summer. But I did just as well in them as I did their counterparts that I took in the school year. So based on what people are saying its not a big deal at all? They were at my university too.
You're fine, I really wouldn't worry about it.