Is it safe to remove the bottom chords of a series of garage roof trusses?
Absolutely not safe. 

Those trusses were engineered with a heavy (critical) dependency on the bottom chords, which are in tension. Removal has left them extremely vulnerable to collapse due to spreading, especially under snow loads, but also under just the load of the roof itself. The roof system is basically a hinge now. 

To get a good mental image, picture yourself standing on an ice rink and sliding your feet outward. How far do you get before your groin starts to scream at you?

Best case scenario, that ridge slowly sags over the opening and looks ridiculous. It will push walls around with it, cracking drywall and binding windows. Worst case, full collapse. Death. Destruction. Worst of all, humiliation.

Repair will require new lumber installed with a suitably fastening system, such as construction adhesive and through-bolts. It may be necessary to winch the walls back into alignment first if sagging has already begun.