MA essentially has no tax deductions for NRs, so unless you worked from home some proportion of the time, you do indeed get taxed on 100% of your income with no deductions. [As a NR, you only have to pay tax on earnings for the days you are physically in MA working, so keep track of business trips, working from home, vacation time, holiday time, etc. That's your only hope to reduce the bill.] There isn't much that we can deduct as a Resident of PRM either, for that matter.
It's good that you can deduct the MA paid amount against your RI tax liability.
I understand that MA is the "high rent" district and thus tends to pay better than RI. Cost of living is much higher here too, although the crooks in politics compete well between RI and MA to see how much of our money they can steal each year.
When we lived in CT, CT didn't have an income tax, so we got royally screwed by RI.
We're well, drop by my real home (NES), that's where I spend a good deal of my time.