When people talk about the 'hostile environment' wrt immigration they are referring to a deliberate set of policies created by Theresa May when she was Home Secretary, with the aim of making life in the UK extremely difficult for those who are not here legally.
Landlords are now required to check the immigration status of tenants and can be fined or imprisoned if they fail to do so, if they knowingly let a property to someone without the correct papers or if the court decides they had 'reasonable cause to believe' that a tenant presented false documents. Landlords can now evict tenants without going to court if they merely suspect them to be illegal immigrants. There is evidence that landlords are increasingly unwilling to take the risk of letting to anyone who does not have a British passport, especially if they are not white.
Until the scheme was scrapped 2 months ago, the NHS was obliged to share patient information with immigration officials. Even though everybody, regardless of immigration status, is entitled to free GP services, those without regular documents are often afraid to access care when they need it. Hospital staff are now required to check immigration status before treatment and demand upfront payment of up to 150% of the cost to anyone who cannot prove their status. Confusion has led to GP surgeries refusing to register anyone without certain documents.
The Home Office now routinely asks DVLA to revoke driving licences of anybody believed to be in the UK illegally. People's homes can be searched if it is believed they hold a driving licence and do not have permission to be in the UK. Only those with at least 6 months leave to remain can now apply for a UK licence.
Schools are now obliged to share pupils' details with the Home Office. There has been some pushback in this area, with parents refusing to answer questions on nationality and birthplace in the schools census and the government has now stepped back on a policy to force shools to share this data. Theresa May wanted to create a policy to make schools put children of undocumented migrants at the bottom of the list for places and to require schools to withdraw places for them. Thankfully this policy was dropped.
There are now increased sanctions on employers who employ anyone without permission to be in the UK, up to £20,000 fine and imprisonment. They don't have to have done so knowingly. It's enough for a court to decide they should have had 'reasonable' cause to doubt the veracity of the employee's documents.
Banks are now required to check the immigration status of both new and existing customers. The Home Office can require the bank to freeze or close the account of anyone without the correct documents.
This doesn't just affect those who are in the UK illegally. It affects anyone who cannot easily prove their right to be here - hence the Windrush scandal. There are all sorts of people affected - those here on a family visa who are fleeing domestic violence, or whose British spouse has just dumped them. Those here on a work visa who have been made redundant. Those whose documents are all with the Home Office while they wait months and months for their visa extension to come through and have only a tatty Home Office letter to explain themselves in the meantime. Those who are appealing a failed asylum claim. Those who have grown up in the UK since early childhood and never even knew they were here illegally until they tried to apply to university.
While the Windrush scandal has forced the Government to scrap or freeze some hostile environment measures, and while there are current legal challenges to some others, there is no big roll-back planned. Sajid Javid has renamed the 'hostile environment' as the 'compliant environment', which I expect will be every bit as successful as the renaming of the minimum wage as the 'living wage':
... there is a belief that as long as May is prime minister, there will be no dramatic departure from the status quo.
“She’s very wedded to this tens of thousands target,” one former official says. “She’s wedded to the hostile environment albeit with a different name. It’s going to be difficult for any home secretary to put their own stamp on things.”
TL;DR - YABU. As a white, British passport holder I have not been subjected to the hostile environment. None of this state engineered racial harassment has happened to me.