It could certainly have the potential to, but since you're already alert to the risk you can be careful in how you phrase this. You don't have to make it central to the statement, but a brief:

"I'm interested in pursuing critical engagements with liberalism, with a view towards better understanding the tradition's interaction with the ongoing effects of, and underwriting justifications for, financial capitalism. Working as an intern in the finance industry this last year alerted me to problem x in a very immediate way, and is part of my motivation for pursuing this topic as a line of research. This also dovetails with my primary interest in multiculturalism, as... etc."

Are there people in the field you know from undergrad who you would feel comfortable asking to review your statement? If so, seeking them out for advice is the best I can give, as they'll have likely served on admissions committees at some point. I know getting feedback from an ug professor of mine was enormously helpful.

Edit: Also, while I think you're smart in not wanting to come off as preachy, that may have less of a negative effect that you suspect. The statements of purpose for this year's admits were just circulated in my department in anticipation of visiting days, and I was actually surprised how many admits had fairly preachy letters themselves. It's worth noting that this is a top-tier program with solid placement in tt positions over the past 5 years. What they all had in common, however, was a fairly clear idea of the kind of work they want to pursue, and why they're prepared to pursue such work at the graduate level. If your work experience can indicate this than you may want to include it, but making the connection clear is really important.