The real problem is that many Christians do stupid stuff. Really stupid stuff that they should be critisized for. Me included.
The criticisms are usually meant for the PERSON, but their professed beliefs get in the way and become the focal point of the criticism. Is this right? Well, it's incredibly important for us to not put a stumbling block OF OUR OWN in the way.
Christianity has enough issues being accepted. People hate us for what we are and they have from the very beginning.
II Timothy 3:12 In fact, everyone who wants to live a godly life in Christ Jesus will be persecuted, NIV
II Peter 4:12 Dear friends, do not be surprised at the painful trial you are suffering, as though something strange were happening to you. 13 But rejoice that you participate in the sufferings of Christ, so that you may be overjoyed when his glory is revealed. 14 If you are insulted because of the name of Christ, you are blessed, for the Spirit of glory and of God rests on you. 15 If you suffer, it should not be as a murderer or thief or any other kind of criminal, or even as a meddler. 16 However, if you suffer as a Christian, do not be ashamed, but praise God that you bear that name. NIV