...is that historically red meat has been a feasting food while fish was much more common.
Until modern refrigeration it was
very hard to keep meat for significant lengths of time. Salting and
curing processes were used but for the vast majority of people having
red meat was reserved for special occasions. This is why it was considered a “feasting” food.
The idea of abstaining from meat as an acknowledgement that we're in a
time of penance and fasting; not a time of feasting. While it may be
part of many of our regular diets today, the meaning hasn't changed; by
abstaining from meat today you're reminding yourself that we're in the
desert of self-denial in preparation for Easter.
This is yet another reason Catholics abstain from meat on Fridays during Lent.