Fairness is subjective. As such, it is not very meaningful to discuss "our fair share of taxes." Ideal communists will substitute "100% of profit" while ideal anarchists will substitute "0% of anything".
Most businesses prioritize their own market value, and subordinate all other motives, including apparent political posture, towards maximizing that one metric. Therefore, they only pay taxes to avoid the negative effects of not paying taxes, rather than out of any perceived moral obligations.
The companies are there because the optimization process that involves jurisdiction shopping determined that establishing a business presence in Ireland provided greater benefits than the other options. There can be only one "best" jurisdiction for any given business entity. Complaining that someone else's seems to be better for more entities than yours is just sour grapes.
If you can't compete on a tax cost basis, there are other ways to attract business: a zero-corruption bureaucracy, privacy or secrecy for principals, reduced reporting requirements, reduced time from initial filing to practice, ironclad and proactive intellectual property protections, strong infrastructure, rock-solid stable units of accounting, or any of dozens of other points that may provide business value that more than compensates for the tax burden.
So fairness is a red herring. It is the objective value that is provided in proportion to the taxes taken that determines whether taxes are "too high" for a business to bear.