At an individual level, it is good actionable advice. At a societal level, it really is just victim blaming. And it is hard to day where the line is between those views.
What sick thought crept its way into our collective consciousness that has made us glorify being a victim above all else. We have been fooled into holding up literally the opposite of success as the highest virtue.
That is, my question is what sick thought made it acceptable to take repression and holding down of full segments of a population under the guise of them individually not standing up for themselves acceptable?
Seriously, the evidence is quite clear that this attitude is complete nonsense and only works for people that have certain advantages already. I get that you feel you have worked hard for your position. So have I. I also get that I was additionally lucky that I was able to reap the rewards of my hard work. Many aren't. And to be ok with that is a truly disgusting collective consciousness problem.
Ahem... citation needed
For this attitude to be accurate, the problem is simply that women and minorities are not educating themselves and/or are not "shopping themselves around." If you want me to cite studies showing that specifically is false, quite frankly I don't have time to dig around for that. You could find studies showing it is true.
You need to study more.
Then compare the cost saving, and time spent on the above, to the marginal cost of your free time. Have you saved anything?
However, careers are what sort of determine how much our time is worth...so it generally ALWAYS makes sense to shop for multiple job offers.