[Boogieman]

You’re taking that passage from Corinthians out of context. The prohibited act is not the eating of the food itself, as evidenced by prior verses. That specific situation is cautioned against, because you may be encouraging an idolator by partaking with him after he declares the eating as essentially an act of idolatry. Buying halal food at a grocery store would be covered much more accurately by verses 25-26 of the same chapter:

“25 Eat anything sold in the meat market without raising questions of conscience, 26 for, “The earth is the Lord’s, and everything in it.””

[MontaniSemperLiberi]

I didn't take that verse out of context. I simply quoted it. I think you did the right thing in looking it up to find out the fuller meaning.

Here is the full section:

The Believer’s Freedom

23“Everything is permissible”—but not everything is beneficial. “Everything is permissible”—but not everything is constructive. 24Nobody should seek his own good, but the good of others.

25Eat anything sold in the meat market without raising questions of conscience, 26for, “The earth is the Lord’s, and everything in it.”c

27If some unbeliever invites you to a meal and you want to go, eat whatever is put before you without raising questions of conscience. 28But if anyone says to you, “This has been offered in sacrifice,” then do not eat it, both for the sake of the man who told you and for conscience’ saked— 29the other man’s conscience, I mean, not yours. For why should my freedom be judged by another’s conscience? 30If I take part in the meal with thankfulness, why am I denounced because of something I thank God for?

31So whether you eat or drink or whatever you do, do it all for the glory of God. 32Do not cause anyone to stumble, whether Jews, Greeks or the church of God— 33even as I try to please everybody in every way. For I am not seeking my own good but the good of many, so that they may be saved.

I think that we agree on the interpretation. If you don't know something is Halal, don't worry about it. If someone tells you it's Halal, don't eat it but don't be offensive either. Christ wants us to be pleasant and inviting to non-believers while being clear what we do believe.