Clickbait. It's more temporary workers.
From anegdotal evidence it doesn't seem that the influx has stopped, 5 years ago it was rare to hear anybody speaking Russian/Ukrainian on the street, now it's a daily ocurrence.
Ukrainian and Polish are very similar languages and after 1 year you can learn the other one and speak with no recognizable accent (my cousin's wife is Ukrainian and nobody realizes that till she tells them).
There are nationalists that do have problems with imigrtion from Ukraine and Russia, but they are a marginal minority, not unlike the nationalists in UK protesting Polish immigration. They don't represent the mainstream opinion and aren't a threat in 99.99% of situations.