Nothing is wrong with hypothizing, or suggesting or even stating anything if you clearly said that this is a hypothesis, or just your opinion. All opinions are welcomed - after all, all theories were once hypothesis or opinions.

Next level of statement is CLAIMING something to be true (say, claiming that there IS time travel, or there IS life after death, or there IS dark matter, etc). If you claim something, (=saying that what you stated is no longer a hypothesis, but is TRUE statement) then you HAVE to show evidence (facts or math or logic) to support your claim. Say, existence of dark matter is supported by detected gravitational field of that matter.

So, saying "God may exist" is a hypothesis which can be discussed, but saying "God exist" is incorrect statement because there are no facts or other evidences to substantiate it (and plenty of facts against, by the way). In such case when you have nothing to substantiate, do not insist that you are correct. Best is to say: my PERSONAL opinion is that God exists, but because there are no facts to support this, I do not insist on it. Nobody would argue with you if you do not insist (claim) something which has no facts to be supported by.

So, claims and opinions are two different things.