I have not heard of the term Desi so before I could comment I had to research this first. Here's what I came up with and perhaps it will benefit others coming to this thread as well.
"Desi (...alternatively spelled Deshi), is a term used by South Asians to refer to themselves (in a manner that avoids any allusion to the specific state of origin and pointing to a common broader identity). This is also a subculture found amongst the South Asian diaspora.
South Asia refers to India, Pakistan, Sri Lanka, Bangladesh, Nepal, Bhutan, and the Maldives, but the diaspora spreads from Fiji to Trinidad, from Kenya to the Persian Gulf, from South Africa to Guyana, from Southall in Britain to Queens, New York, and many places in between.
The term comes from a Sanskrit word ... "Desh" ("nation" or "the motherland"), borrowed by most South Asian languages. It means "countryman" and it is used even amongst people who may have roots in a different country from them. Amongst people from the Indian subcontinent, especially in English-speaking First World countries, this term refers to the blend of cultures and identity of the South Asian communities, crossing national and cultural boundaries that separated them in their ancestral countries. Moreover, many of their ancestors left the Subcontinent before its partition or some of them have mixed Desi background and consequently don't relate to a single native country. South Asians living outside South Asia now refer to anything or anyone related to their countries or culture as Desi or Deshi"
Wikipedia
There is quite a bit more interesting information but this is the core of it that relates to the subject at hand.
As far as I've seen it seems like people are much more willing to voice their negative feelings with regards to any race, culture, or religion when they are able to voice it within the anonymity of the internet. I, myself have been tempted to voice negative opinions even to particular people in chat who have been of a different race or culture that is at the moment clashing with me. I am not normally a vocally racist person and in general am not very racist. I think the internet gives us a freedom to behave in a way other than our ego would normally allow our ID to behave.
Granted in large groups people tend to form a mob mentality and follow the leaders in the crowd more easily. I don't think this seems to occur as much as in past times because of the level of law enforcement in force at this time.