It is said that there is no standard for IoT Protocol Communication. What does it mean to say that?
I think what you mean to say is, the on field M2M communication protocols are not standardised for e.g, some devices use zigbee, some use zwave some use ble etc.
So in a premises when you have multiple devices from multiple vendors all implementing different protocols like the ones mentioned above, it becomes a problem to fetch the data from all these devices as you need a middle layer/device which would support all these different protocols fetch the data and push it forward. So there is no single communication protocol used by all manufacturers. This is what people mean typically when they say there is no standardization of protocols for IOT.
Protocols like MQTT and CoAP are typically used for exchange of data between a field gateway and a remote server (like the azure iot hub).
Hope it made sense.