I think those two phenomena are qualitatively different. Sexual harassment is about using an official function on a job for personal ends of the sexual nature - either to obtain sex or to demonstrate sexual prowess (macho image etc.). Exclusion of women from ceratin jobs, by contrast, has nothing to do with sexual favors - it is about enrty barriers to an occupation. For that matter, the exclusion of women is the same kind of phenomenon as the exclusion of, say, Blacks - its is employment discrimination, and NOT sexual harassment.
A male boss harassing a female clerk usually does not intend to exclude in any way females from clerical positions. All he wants is a sexual favor from a particular individual.
On the other hand, male electricians or truck drivers 'harassing' a female electrician or a truck driver, however, do so primarily to exclude a certain group of people from that particular occupation, rather than to obtain sexual favors or demonstrate their sexual prowess. Their action is about jobs, not sex, as they may harass other 'undesirable' groups as well, Blacks, Asians, or even other White males. The Nation run an article several weeks ago arguing that even 'wimpy' White males can be harassed by their colleaugus on ceratin jobs, because they are perceived as 'unfit' for that particular occupation.
I also think that defining the latter as 'sexual harassment' delegitimizes, in a way, the rights of individuals as workers. It redefines work-related issues as civil rights issues, and that signals that work as such is a 'non-issue' in this country. BTW, we have thousands of public-benefit tax exempt organizations in this country working on a wide variety of 'rights-related' issues, from humanitarian aid world-wide to helping injured animals. Interestingly, workers' rights is not one of them, in fact, pursuing such a goal is a sure way to lose the tax exempt status.
Regards,
Wojtek