My preference for FPTP is more technical.
Bearing in mind the rarity that a party will reach 51% of the popular vote, coalition governments become the norm. Which, imo, isn’t what the electorate votes for (in most cases). Let’s use this election to make a hypothetical example:
Labour is currently polling at 45-46% so would need either the Lib Dems or Greens to form a coalition. Why should a junior party have the power to force through policies the electorate didn’t give a mandate for?
Continuing with the this election as an example, I believe the party with the most votes should form the government. Labour polling on 45%, hypothetically could be thwarted by a coalition of the other parties. This happened in Spain this year where a centre-right party ‘won’ the election but the centre-left party formed the government. In the Netherlands, Geert Wilders ‘won’ the election but will not be the next PM.
PR systems tend to be more fragmented to parties rarely poll above 40% so tend to need ‘rainbow coalitions’ (multiple parties) and governments can be brought down by these junior parties.
Take Brexit for example, at 52:48, if we had a PR electoral system, we wouldn’t have had a decisive conclusion to that issue. FPTP delivered a government with a large majority to push through their agenda, likewise with this upcoming election where Labour. The term ‘elective dictatorship’ is apt and actually, a perk of our system.
As for 16-17 year old votes, there’s a reason most countries only enfranchise them for local/municipal elections rather than national elections.