Muslims should always help in any good work and avoid helping in wrong. Allah (SWT) says in Quran (And help and co-operate in good and piousness, and never help in sins and wronging others) (Sura 5, Verse 2).
We should not help in wrong worship because it is based on injustice and it ignores the Truth sent by Allah (SWT) on His last Prophet Muhammad (SAWA).
What you named it as Holy Water, can you prove that it is Holy? How it became Holy? By whom?
We have to be accurate in naming things and not blindly follow others.