We could experiment with Taiwan's system where students have
language lessons in Minnan (aka Hokkien) and Hakka, depending on
thier dialect group. The rivalry (if there is one), between the two
groups is amicable. So to say that speaking different dialects will
lead to a fragmentation of the Chinese community is inaccurate at
best.
I think the problem lies in the fact that English is now
supplanting all types of Chinese as the lingua franca of the
community. Therefore, there is a fear that teaching or even
encouraging dialects will lead to confusion amongst the young,
further weakening their grasp of Chinese in any form. We've already
seen this in the young adults today. Brought up by dialect speaking
parents, they were made to switch to Mandarin and then English.
Now, they probably cant speak any one of them properly.
Nevertheless, i think that young students should be made aware of
their identity as a hokkien or cantonese or whatever. Being part of
a dialect group, or being able to speak dialect, should not be a
source of shame. I've seen parrents with hokkien surnames e.g. Ang,
Tan etc naming their children Hong and Chen. This
hanyupinyinization of names signals a troubling mindset, and
probably reflects the attitudes of many Singaporeans today.