"... difference in perception Indians have of westerners who adopt certain Indian cultural traditions depending on the generation they are in"
I didn't read the article yet (catching up on things) but reading the OP, I understand what FH is saying about the younger generation giving a bit of cold-shoulder to Westerners, whatever, could be for that matter Africans or Japanese or Chinese etc. and even fellow Indians, who show interest, enthusiasm for or engagement with Indian culture or Hinduism.
I am a "Westerner" married to an Indian, my personal observation is - it also depends on "where you are at the moment", but there is some truth in her feeling.
For example, when I was in Canada recently, and doing some shopping at Indian shopping centers in Surrey (there is one HUGE one there with hundreds of stores and businesses in one giant center of new modern complex), with Indians at the time of shopping (not sure if that made a difference) all the "my generation" in age group never gave me a second look, I was even a favorite, customers were just wonderful to me, the "shop owners" gave me the same service as anyone else, etc..
The young, teens, in a CD shop (buying modern "pop" cds though in Hindi or Punjabi etc) be they Hindu or Sikh, were 50-50, some indeed were more cold. My distinct feeling is, while not fully "Westernized" into "Canadian culture (? is that the word)", still there was a feeling they wanted to project "not Indian".
Does "not Indian" sound strange? But that is the words that fit in my observation.
Hmmmm... so it wasn't so much "anti-ShivaFan" because I am "not an Indian" (like them), but more the teen saying "I might be Indian, but I am 'not Indian' so you should be on my side and be mean to those who like India" (sounds strange, but ....)
In the Hindu temple, teens were not so obvious about that as in the CD shops.
So for what it is worth, that is my observation in Canada. However, my observation in US is somewhat the same, but teens (of Indian background) as less so in the "not Indian"mode of projection, and instead "I am Indian and smarter than you" mode. Of which many are smarter than me.