You shouldn't have to sell your soul
In black and white
They really, really ought to know
--Tears For Fears
The left loves employing positive substitute symbols because of rhetoric's capacity to deceive. A current favorite is 'immigration.' People tend to have a natural affinity for the term because, by and large, their ancestors were immigrants. This is true for most people in most countries, as the history of man can be told as a story of migration.
We Americans are particularly fond of the immigrant term as it conjures recollection of our E pluribus unum founding and millions subsequently pouring out of ships at Ellis Island in search of better lives.
1882-S $1 Morgan PCGS MS67 CAC
Leftists omit 'legal' from the immigration discussion out of political expedience. The millions of illegal immigrants currently residing in the US have been a source of votes. They also support a statist agenda grounded in globalism. Former President Obama's lawlessness with respect to enforcing immigration law exemplifies the left's position.
Because leftists know that they would have difficulty making their case to most Americans that illegal immigration is a fine thing for the country, they must restrict the narrative to immigration only. Then, the accusations fly. Those who support Trump's Wall or other methods of immigration law enforcement are painted as anti-immigrant. Or xenophobes. Or nativists.
If the name-calling grates on enough people, however, then the positive substitute symbol strategy could very well backfire. Americans are likely to become more conscious of the difference between legal and illegal immigration.
Not sure the left wants that to happen.