Let us try some common sense. The question really is lot of practicality versus a meat or not meat issue. One can eat meat and go to Gurdwara or go to Gurdwara and eat meat after. So we are talking about say 30 minutes or an hour of body time.OK, clearly alchol is prohibited for Sikhs. There is no question or doubt over it. People who bring or consume alcohol in the Gurudwara should get the "massa rangar treatment".
The meat issue again??? We can say that meat should not be server in the Gurudwara as the langar is open to everyone and for a lot of reasons it would offend people. However, meat consumption is not an issue for Sikhs. I don't know where people are going with this. If people want to really respect Sikhi then they should learn, understand and live according to Gurubani. Perception of respect in front of others does not have much value.