One thing to keep in mind is anti-Chinese sentiment was almost universal during this era. We're all pretty aware about Jim Crow laws in the South, but many similar statutes existed in California. For example, California schools were segregated from 1850 to 1930 against Chinese. These policies had near universal support. For example, an 1879 referendum banning Chinese from public employment passed with 99.4% support. White people really hated the Chinese at the time, and I'd be careful about singling the Irish out for special hate.

That said, one of the main locuses of conflict in California was over wage labor especially on the railroads. For example, the first transcontinental railroad was built in the late 1860s. The Union Pacific, working from the east coast, recruited heavily from Irish immigrant communities. The Central Pacific used large numbers of Chinese workers, and there was a lot of competition between the teams. Irish workers actively worked to sabotage Chinese crews. They jeered and verbally abused Chinese, attacked Chinese with pickaxes, set of charges in ways that would deliberately endanger Chinese workers. It's really ugly.

I think the core of the conflict, in addition to the ugly racism of the late 19th century, was conflict over wages. Workers were getting increasingly organized during this period, and Irish workers were often at the forefront of greater organization during this period. An example can be seen in the Rock Springs massacre in 1886. The mine had historically been whites only, but due to strikes by miners, the mine started hiring Chinese labor. By 1886, two thirds of the miners were Chinese. Miners were paid by tonnage, and although the rates were the same, the mines had a general policy of giving white workers better positions to mine in. A general policy of equalizing these inequalities was interpreted by many workers as actively favoring Chinese. This eventually led to a brutal massacre in 1886 when 28 Chinese were murdered. There was a real fear that Chinese were willing to work for less than white workers, and that Chinese would end up replacing much of the white working class.

In the middle of the 1877 recession, the Workingman's Party in San Fransisco held a meeting on some vacant lots. The two leaders of the Workingman's Party were Frank Roney and Denis Kearney, both born in Ireland. The meeting quickly turned anti-Chinese, and it was the first of many anti-Chinese riots. It's not so much that the Irish were especially anti-Chinese, but the fact that a disproportionate share of the white urban working class was Irish, meant that much of the most virulently anti-Chinese actions were led by people of Irish descent.

Excluded, Segregated and Forgotten: A Historical View of the Discrimination of Chinese Americans in Public Schools

Nothing Like It In the World: The Men Who Built the ranscontinental Railroad, By Stephen E. Ambrose

The Indispensable Enemy: Labor and the Anti-Chinese Movement in California, By Alexander Saxton