well i think its really a relative term, "insecure". its mostly a cultural thing (cant speak for all asians, really only the orientals), a big "virtue" embedded in our culture is humility in everything we do/say, as well as being more reserved in front of people you dont know that well (sort of having two "faces" as it were)
in western culture it may seem insecure because on a RELATIVE basis, westerners are far more confident and outgoing in general
i mean back home no one would say a person is insecure if that said person downplayed his achievements and said "no theres always someone better than me, im not that good at all", its a sign that you know your place and arent being arrogant, and you are respected for that back home, whilst here its perceived as insecure
westerners are also a lot more outgoing (in general), i mean, its really normal, even in central london, to strike up a friendly conversation with the shopkeepers or taxi drivers or really just opening yourself to strangers, whilst back home, its seen as invasive and inappropriate, people who take the initiative to "open up" to strangers are either crazy, drunk, or attracted to the person they are trying to talk to
no perception is right or wrong, it is after all, a perception