Edit: Jesus Christ, people. If you buy a $150 Thinkpad made by slave labor instead of a $1,200 MacBook made by slave labor, you're still supporting a capitalist economy based on slave labor. We all do. We have no choice. The number of smug liberals in the comments saying "well I buy a cheap used laptop" or "well I buy coffee beans and make my own coffee" are completely missing the fucking point.
Don't tell yourself your consumption is moral. All of us make unethical choices every day because there is no ethical consumption under capitalism. Accept your shame and guilt and let it drive you to do better.
Buying used means you aren't actually contributing to slave labor at all. Buying new would.
Also where are you getting this laptops are made with slave labor idea? We aren't talking clothing here.