IOS 7 - Google Calendar - Fantastical edit mode shows GMT timezone
GMT, also called UTC or Zulu time.

Is the basis time (zero) for all time zones clocks world wide.

When the Time Zone Support is turned on, the Calender will rightly so show the GMT for you to decide which time zone is to be used. 

It has to do that logically, since you are on time zone support (means automatic switching the time zone) if you travel. So you have to tell it which time zone to use as fix point for that event.

Let me try to make it clearer:

You set a meeting for the Vancouver time at 8:00.
Now you travel to New York and the Calender will automatically move that time to New York time, if the time zone support is turned on, if it is not turned on you would miss that meeting reminder, since it will still show as Vancouver time.

You can either leave it on, and choose the time zone, or turn off the time zone support. If you do not travel outside your PST time zone you do not need the time zone support.

But...there is always a "but".

If you have meeting attendees from different time zones, and not always up to speed of the time differences, calling a meeting at 16:00 Vancouver time with someone in NY would mean 19:00 for them. Here is where the time zone support comes handy for you to look up.

In your Fantastical 2 you can turn it on/off here: