There are two possibilities. These monks are either:
1) Vajrayana Monks -- Tibetan monks usually wearing red (and
yellow) robes such as these:

(The 14th Dalai Lama)
2) They are fake monks. These types of "monks" are very common
nowadays, they wear monks robes and beg for money out there. No
real monks will beg for money outside.
Can you describe the kind of robes you saw?
In Buddhism, there are three traditions of Buddhism: Theravada
(Thai, Sri Lanka, Burmese traditions), Mahayana (Chinese) and
Vajrayana (Tibetan). Monks from the Theravada and Vajrayana
traditions are allowed to eat meat, however Theravada monks only
receive food by alms giving and not by buying food from
coffeeshops. Mahayana monks are vegetarians due to Bodhisattva
practices. Tibetan/Vajrayana monks are allowed to eat meat in their
culture because Tibet is a very remote, mountainous region which is
not suitable for vegetation.
Even though Buddhists whether from Theravada, Mahayana or Vajrayana
traditions are allowed to eat meat, we only eat meat under 5
conditions:
http://www.jenchen.org.sg/vol5no4a.htm
...Buddha understands the ignorance and habits of sentient beings
that have accumulated from aeons of their many past lives. In order
to provide sentient beings with an expedient means of embracing
Buddhism, those who are not able to convert to a vegetarian diet on
a long term basis are permitted to consume meat provided:
(1) That he did not slaughter the animal personally
(2) That he did not instruct others to slaughter
(3) That the slaughter was not committed for his sake
(4) That he did not witness the slaughter
(5) That he did not hear the cries associated with the
slaughter...
Under these conditions, the meat is considered 'karmically
purer'... because it is not due to direct killing, no direct link
with you, the karma is generally lighter. Of course vegetarianism
is still recommended. However personally I am not a vegetarian yet.
I am from the Mahayana tradition.