Lojda is just not a good player, but he definitely should have played a clay event. Conversely, I think Zeballos should have come here but he didn't. Goes to show where priorities lie. Some guys are more wanting the experience to play a major, others want to get to the top 100 to make them directly.
I don't think that is entirely fair. I've seen Zeballos play at Roehampton, and he was very passionate to be there (even if he played really poorly). The main difference is that he has already played in the main draw in Wimbledon, so he no longer has to dream about playing there. Plus, he probably realises that he has never done well on the surface so it is better to get those much-needed ranking points in a Challenger.
For Lojda, I think Wimbledon remains a rather elusive dream.