Many people accept answer to this question as No without thinking over it. Questions like these use the cognitive biases in our mind to collude our thoughts.
Most people answer to this question as No because they think that answering it as Yes might make them feel like insensitive to the needs of poor. Most of the leftist/socilaist and communist logic works on this principle. For example when one opposes reservation system, it is claimed that a person is against downtrodden people and so on. Read any newspapers and you will get more examples.
Societies have failed have got mired in abject poverty and misery because these societies projected answer to above metaphorical question as NO.
Let us apply some economic reasoning to the question in the title. Looking at alternatives is the best way to make things clearer. One of the insight you gain out of this is that we can never judge other person’s decision to economize his resources through our perspective.
Economic reasoning involves looking at alternatives which are mutually exclusive. In this case two alternatives are thrown into our face. Either spend milk on God or spend it on a poor man. Giving milk to God will keep the man hungry and malnourished which is your fault. Let us call this scenario 1.
This would have been a fair alternative if each one of us got equal amount of milk magically while randomly some people did not. In reality milk is produced by a farmer who then sells it for a money wherever there is demand. A devotee has to work somewhere to earn some money in order to buy that milk.
The first choice here is that devotee who thinks offering milk to God is stupid can simply not work or work less and rather spend that extra time with his family. Somehow this choice does not seem evil at all. Social media is full of letters by little kids who demand some time from their busy parents. How often we hear people crying about culture and all that because young people these days spend too much time on their career ?
A person who works extra, earns little extra which he then decide to spend on whatever he wants. Offering milk to God is one of the countless motivations that make people like you and me toil at our workplace. None of us works for us to “feed the poor hungry man”. Lets call this alternative 2.
Hypothetically speaking, if each one of us was given a fixed amount of time and if were were asked to divide that time into two unequal portions such that whatever is the outcome of one portion will go to poor people and outcome of second portion will go to his personal needs. Without any exceptions most people will allocate more time to their own needs.
In reality we do this sort of decision making all the time. We all spend money on poor people but it is generally a small portion of our earnings. We keep most of the money for ourselves and for our children.
Communist societies refused to see this basic human nature. They thought that everyone should work and the output of their labor must be divided among all people. The productivity of such society was far too low, there was always a scarcity of everything and eventually the society and country collapsed.
This is the reason why we can never judge how people spend their money and what motivates them.
Of course some people argue that wouldn’t it be nice to have a society where everyone feeds the poor before offering anything to an idol ? The reality is that this is not natural human behaviour in society. There is no society on earth which has ever practiced this sort of behaviour willingly. Those societies tried to force this behaviour got obliterated pretty quickly.
That is why, the logic that Mr. X should not to Y with his money but spend it on poor is bullshit logic not worthy of admiration but scorn.