It is not possible for an Indian citizen to get a tourist visa. Indians can get visas for religious tourism which is very restricted. It means traveling in a group with a specific itinerary. They can also get a visa for visiting family. Obviously, you need some close family in Pakistan for this and it is difficult and time consuming to get. Here you can travel only to one or two specific cities and need to register with the local police there and report to them frequently. Apart from that, you can go around freely. Some people I know are married to Pakistanis and have visted in this manner. Indians can also get a business visa but again, you need an invitation from a business body in Pakistan. Please note that these restrictions are on a reciprocal basis. India imposes similar restrictions on Pakistanis as well. A little easing was done during Dr Manmohan Singh's tenure but things became stticter under BJP.
For your second question, no a Pakistani visa doesn't create any issues in travel to the US or G7 countries. Millions of Pakistanis citizens live in the US, UK, France and Germany and many travel to Pakistan quite often. In addition, many Americans and British visit Pakistan for tourism. Not in millions but in a few lakhs per year. A few relatives of mine from the UK have visited as well.
Coming to your third question, it is fairly safe. Terrorism was a major issue about 15 to 20 years ago but today it isn't as bad. Karachi used to be very dangerous earlier due to gang violence but it is better today. It is similar to India in most respects. As long as you don't go around disrespecting Islam or the prophet, no one will bother you. Indians look similar in any case. People who speak Hindi/ Urdu and Punjabi can easily pass for a Pakistani. I had several Pakistani friends and acquaintances in the US and UK and when visiting their events, families or restaurants, no one thought I wasn't Pakistani. I have visited Pakistan once for 2 weeks about 15 years ago and no one ever thought I was an outsider and no one bothered me apart from the usual things we see in India. I visited Lahore, Islamabad and Murree (a hill station). I went as a tourist as I have a foreign passport. You can search YouTube and you would find plenty of videos of American and British tourists in Pakistan as well as foreign citizens of Indian origin who have even driven across Pakistan to India.
It's really interesting as I am in fact applying for a visa right now! Now they allow an evisa which is easier (not for Indian citizens obviously). Non Indians can travel anywhere amd don't need to register with the police etc. Let's see if I get the visa. Will travel around September if approved.
Note: please don't start a political or religious argument. The answer is simply a response to a question. The purpose isn't to glorify or defend Pakistan.
