The importance of social symbols of gender
Our (inner) gender needs to express itself, to live itself out in the society (which is the only life we know). For this it hunts for social symbols fixed by the society (gender roles) for that particular gender.
Thus if females in a society wear different clothes than men, the expression of femininity in males will be centered on choice of clothes (i.e. such males will wear the clothes meant for women).
It does not mean that those clothes (e.g. skirts) are inherently feminine (remember macho Scottish men also wear skirts). More importantly, it does not mean that the femininity of the males flow from their clothes.
The clothes are not the source of their femininity. They are just an expression of the feminine gender within them.
There are societies where females and males wear the same clothes (e.g. Polynesian societies) but their social differences lie in the different works assigned to males and females. The feminine gendered males (third gender) express their femininity by choosing the work assigned to females. In such cultures there is no concept of transvestism.[1]
Thus transvestism does not exist in nature (whether its animals or humans). However, feminine gender in males definitely exists in nature.
Thus transvestism is only a social role adopted by the third gender as an important assertion of their inherent femininity in societies which have distinct dress codes for men and women.[2]
Having receptive anal sex with men is similarly not a feminine attribute in itself. Rather it's adopted as an assertion of their femininity by third gender males, in societies which socially equate being receptive partner as the exclusive role of females. Males in 'third gender' spaces have as much pressure to prove their 'femininity' by being 'fucked', as men in 'masculine gender' spaces have to prove their 'masculinity' by 'fucking'.
Note that while masculine gendered males may too indulge in receptive anal sex at times, for third gender (e.g. Hijras) it is a symbol of their 'femaleness') and they indulge in it exclusively (or pretend as such).
Similarly, the masculine gender in men (1st gender males) also needs to assert itself, and it similarly hunts for the 'acceptable' signs of manhood in the society (male gender roles).
Cigarettes, alcohol, homophobia (sic), and heterosexuality are not intrinsically masculine qualities/ things. However in a society (western society in particular) which holds them out as important, even requisite symbols of manhood, men will compete with each other to display these qualities --- as a social assertion of their masculinity, creating a false impression that these qualities are inherently masculine.
This entire conforming-to-social-roles business is especially an acute issue for men because the society will not acknowledge their masculine gender unless they exhibit the above mentioned traits.*
In societies that do not fix 'homophobia' as a social role of men, men do not display it at all. An example is the contemporary society in some parts of
References:
[1] Johanna Schmidt; Redefining Fa' afafine: Western Discourses and the Construction of Transgenderism in
URL: http://wwwsshe.murdoch.edu.au/intersections/issue6/schmidt.html
[2] Again the same para above explains that due to the effects of westernisation, as men and women start wearing different clothes, the concept of Fa' afafine has become almost ssynonymous with transvestism.
[3] Maura Reynolds;
URL: http://www.sodomylaws.org/world/afghanistan/afnews009.htm
[4] Hank Hyena; Semen warriors of
URL: http://www.gettingit.com/article/56