I Don't Get Protesters

The last couple of days, there have been protests around my work. People are apparently protesting the reduction of wages for janitorial staff at large companies as a result of cost-cutting measures. We have been informed that they will be protesting all week, and that we should just be prepared to deal with all the noise, delays, and annoyance which will accompany them, because apparently we can't do anything about it. Now, I respect people's right to free speech and the ability to protest (as long as they respect other people's rights in the process, which, as an aside, these protesters do not, as they readily trespass on private property), but I just don't get the point of these protests; perhaps someone can enlighten me on what they are trying to accomplish. Let me explain further.

Firstly, the composition of the protest group. There are roughly 100 people, who all get bussed to and from the protest: they are not local (as far as I can tell), or connected to any local business in any meaningful way. The largest group is the marchers, with standardized color-matching protest shirts, and standard union protest signs. There are also security people, who coordinate displacing the normal people in the area so the protesters can march through. There are also a few union thugs in suits, presumably there to intimidate anyone who might oppose the protesters.

Then, there's what they do. Specifically, they march for roughly an hour or so, blocking walkways, driveways, intersections, bridges, and impeding anyone they can. They carry drums and bullhorns, so as to make as much disruptive and annoying noise as possible. There are a couple of special-interest signs (eg: promoting a politician the unions favor), but most are standard union-support signs, in English and Spanish of course. They pause in front of some buildings, but mostly they just unload, walk through being as obnoxious as possible, load up, and move on to the next protest site.

Now, what exactly is the point? I mean, here's what I get from the protests, in no particular order:
- These people don't care about the local businesses, they're union stooges bussed in from who-knows-where
- They don't care about jobs for Americans, just jobs for union members and people who can't/won't learn/use English
- They don't have any clue about what policies or politicians are good for jobs and the economy, so they are extremely hypocritical
- They don't care about anyone else, or the damage or inconvenience they impose on anyone else
- They want people to respect their rights, while they trample on other people's rights without a second thought
- They are spending an entire week working every day to solidify my contempt for their organization and whatever they stand for

Their protests make me want to support the businesses they are nominally protesting against, oppose their political causes, and seek and moral and legal justification for doing them physical harm. I can't imagine that's their nominal intent, but I also can't see what they think they will be accomplishing, other than providing something to justify the salaries of all the protesters and support people who are on the union payroll. Are they collectively too stupid to extrapolate the resulting sentiment, or am I not experience the typical/expected reaction, or... am I missing the point of these protests?

Update: Apparently these a-hole protesters will be busing in more people for tomorrow's protest, and randomly blocking/closing streets in the area between noon and 6pm. And, astoundingly, the LAPD will be complacent and supportive to their activities, helping them aggravate the local employees and patrons while facilitating their ability to otherwise break the law. The SEIU union will get no support from me ever, for what it's worth.