All religious organizations that freely do charitable work that helps other people not of their own religion should be tax exempt, as this saves governments vast amounts of money. Genuinely charitable organizations that are also religious help the poor and homeless and drug/alcohol addicts and so on. They provide services to the public that are desperately needed - doing so in the name of their religion - that's what motivates them. If they were taxed by government, they would be unable to provide such services, and the government knows it would then be left to pick up the tab for what those religions do in the public sector.
On the other hand, we all know some organizations have claimed to be religious when they are not, just to get tax exemption. Those groups should not be tolerated by governments, yet the trouble often is that the corruption used by those pseudo-religious organizations has crippled governments. There are also other religious organizations that make a token gesture at helping the public, to maintain a charitable, tax-free status, but they only help their own first, with a few favors cast around to some not in their religion, to keep their status. They should not be tolerated either.
What you cannot do is tar all religious organizations with the same brush.