I like Paul's lengthy explanation about how everyone should be convinced by their own conscious what practices they wish to follow, so long as it is to them how they honor God. From Romans 14:
Accept the one whose faith is weak, without quarreling over disputable matters.
2One person’s faith allows them to eat anything, but another, whose faith is weak, eats only vegetables.
3The one who eats everything must not treat with contempt the one who does not, and
the one who does not eat everything must not judge the one who does, for God has accepted them.
4Who are you to judge someone else’s servant? To their own master, servants stand or fall. And they will stand, for the Lord is able to make them stand.
5One person considers one day more sacred than another; another considers every day alike.
Each of them should be fully convinced in their own mind.
6Whoever regards one day as special does so to the Lord. Whoever eats meat does so to the Lord, for they give thanks to God; and whoever abstains does so to the Lord and gives thanks to God.
7For none of us lives for ourselves alone, and none of us dies for ourselves alone.
8If we live, we live for the Lord; and if we die, we die for the Lord. So, whether we live or die, we belong to the Lord.
9For this very reason, Christ died and returned to life so that he might be the Lord of both the dead and the living.
10You, then, why do you judge your brother or sister
a ? Or why do you treat them with contempt? For we will all stand before God’s judgment seat.
11It is written:
“ ‘As surely as I live,’ says the Lord,
‘every knee will bow before me;
every tongue will acknowledge God.’ ”
b
12So then, each of us will give an account of ourselves to God.
13Therefore let us stop passing judgment on one another. Instead, make up your mind not to put any stumbling block or obstacle in the way of a brother or sister.
14I am convinced, being fully persuaded in the Lord Jesus, that
nothing is unclean in itself. But if anyone regards something as unclean, then for that person it is unclean.
15If your brother or sister is distressed because of what you eat, you are no longer acting in love. Do not by your eating destroy someone for whom Christ died.
16Therefore do not let what you know is good be spoken of as evil.
17For the kingdom of God is not a matter of eating and drinking, but of righteousness, peace and joy in the Holy Spirit,
18because anyone who serves Christ in this way is pleasing to God and receives human approval.
19Let us therefore make every effort to do what leads to peace and to mutual edification.
20Do not destroy the work of God for the sake of food. All food is clean, but it is wrong for a person to eat anything that causes someone else to stumble.
21It is better not to eat meat or drink wine or to do anything else that will cause your brother or sister to fall.
22So whatever you believe about these things keep between yourself and God. Blessed is the one who does not condemn himself by what he approves.
23But whoever has doubts is condemned if they eat, because their eating is not from faith; and everything that does not come from faith is sin.
So, if nothing is "unclean", then if one can relate to God through say, Krishna, and veneration of Krishna brings them closer to God, and in their mind they understand that "all things are done to the Lord," how is this sin? How is holding forth Love, over and above any "doctrinal purity" not worshipping God? Doesn't the notion of "doctrinal uncleanness", contradict Paul saying "nothing is unclean in itself"?