I think this is true but not completely true. If a persons beliefs actually do entail the sincere belief that they are here to give no ground against rebels against a sovereign Lord, to not even listen to the other because they do not share the same presuppositions - that makes friendship difficult (nulls the belief is purely notional - a form of words that does not touch the person in their heart). IF a sectarian Calvinists goes to the extremes of Rushdooney, for example, in developing this stance again - unless the belief is notional - it’s going to make friendship almost impossible. I think we need to respond to other people as we find them and be realise that God’s children are everywhere and each person is a child of God in the making. However, sectarian Calvinism taken to a an extreme can easily become an ideology that promotes division and even hatred (as it did in South Africa, and as it does when sectarian Calvinists divide in acrimony over smaller and smaller points of doctrine perhaps splitting up families and friends who never speak again)
Hi Kate - Billy Graham is an interesting old fruit. Of course he’s not a Calvinist but he still believes in hell (but probably these days more along the lines of hell being our rejection of God rather than God needing to torment those who reject him). He was a hard nut in his youth - and he was still a bit of a hard nut when I saw him preach in 1973 (and I was very, very young!!!). However, he has always been open to other Christians who do not share his views and has become increasingly open to them as he has got older (and has often been hardly criticised by other Conservative Evangelicals in the USA for this ). So it is openness and love - or the absence of it - which should guide our discernment of those we disagree with IMHO