Good catch, but there's a little bit more to it actually.

I recorded a video on this recently:

https://www.youtube.com/watch?v=rthHop6afZU

The problem with the bottle on the right is two-fold:

1. It's plastic so you're actually eating micro-particles that have negative long-term health consequences.

2. Because the bottle is standing like this, as the pressure builds up, sometimes when you open it (without squeezing yet) it bursts ketchup all over the counter.

So neither is perfect, but I'd still go with the glass bottle! :)