So put to death the sinful, earthly things lurking within you. Have nothing to do with sexual immorality, impurity, lust, and evil desires. Don’t be greedy, for a greedy person is an idolater, worshiping the things of this world. - Colossians 3:5 NLT
Because of these sins, the anger of God is coming. - Colossians 3:6 NLT
Why these sins in particular? I can't say I know the answer to this. So I'll simply share thoughts.
1) It could be that these were very specific struggles for the church in Colossae. Remember, Christianity isn't something people have grown up with at this time, so there has been a lot of dabbling with other religions and beliefs.
2) Scripture says no sin so clearly affects the body like sexual sin. "Run from sexual sin! No other sin so clearly affects the body as this one does. For sexual immorality is a sin against your own body (1 Corinthians 6:18 NLT)." So, the importance of God's anger due to these sins can't be stressed enough.
3) If greed can lead to idolatry, then it's leading people away from God. Greed won't lead people to serve but to be served. It won't lead to generosity but to stinginess. And if it's that easy to idolize materials, how much easier will it become to idolize one's self?
All in all, I'd say any of the above is a start for why these sins can infer God's anger. Let's be clear, God hates all sin. Sin places a barrier between us and Him. God does not want a barrier between us, that's why He sent Jesus. God knows the full effect of sin, and in His love, He wants to save us from its destructive patterns. The question is, do we want to be saved?