Erek, no-one's signature will display! That's because some people abused the signature system and posted rude or insulting signatures.
As for your difficulty with a couple of thuggish pilots at that flying school, please ignore them. Poland will be full member of the EU from May, and you will be as entitled to a job here as any other EU citizen. Equally, any British people will be entitled to work in Poland. However, with the aviation business still suffering post-9/11, you can expect to encounter more hostility from others who see you as a threat to their chances of getting a job.
Explain to them that the UK legislated to allow you this opportunity, and nothing they can say can deny it to you. If they don't like it, that's their problem.
Scroggs